Crossbone Isle (Golden Sun)
- This article is about Crossbone Isle as it appears in the original Golden Sun. For the incarnation of the island in Golden Sun: Dark Dawn, see Crossbone Isle (Dark Dawn).
Crossbone Isle (宝島 Treasure Island) is an optional, endgame-level dungeon in Golden Sun. It is located somewhere in the Karagol Sea, and Isaac's party has the opportunity to discover and explore it during the late stages of his quest. It is filled with nine floors worth of complex puzzles guarded by a wide variety of strong, boss-like variants of existing enemies, and it leads up to a fight with the game's strongest optional boss, Deadbeard. It lives up to its in-universe reputation as an island loaded with exotic and ancient treasure the envy of modern-day pirates the world over.
While the main method of reaching Crossbone Isle is to ride a special tornado hidden in Suhalla Desert, a much better-hidden method of temporarily accessing the earlier part of the dungeon exists during the Tolbi-bound Ship sequence that takes place significantly earlier in the game.
Methods of access
The official method of reaching Crossbone Isle presents itself to the vast majority of players as seemingly the "only" method in the game. Somewhere in the middle of Suhalla Desert's latter screen, the party can cast the Reveal Psynergy at a gap visible to the left at the cliffs just before the part where the Storm Lizard's giant tornado chases Isaac down, exposing an earth pillar leading to the Mars Djinni Flash. Behind it is a cave leading to a giant pink tornado. If you cast Douse on this, you will fight the extremely similar Tempest Lizard boss, but you can instead let the tornado carry you off the screen. This will deposit the party not outside the village of Suhalla like the other tornadoes, but at Crossbone Isle itself.
While at this special region of the overworld map, bringing up the map screen will bring up the message, "This place doesn't seem to be on the map...", and the dot that normally represents Isaac's party will not show. The small zone of open grass at the center of the island, surrounded by mountains and forests forming a "ring" around it, will bring the party into the first screen of the dungeon — presented as the outdoor screen connecting to the cave leading down into the depths — despite not showing an overworld icon. Incidentally, the portion of the dungeon that begins with the cave just past this initial exterior-level screen is referred to in the in-game save menu as "Crossbone Isle Cave" (宝島どうくつ Treasure Island Cave), even though that title does not flash onscreen as you step inside.
The Tempest Lizard's pink tornado will remain spinning at the northwest beach, and letting it carry the party off again will deposit you near Suhalla "as normal." However, it is possible to cast Douse to fight the Tempest Lizard at this beach. Once slain, the pink tornado will disappear — but it will reappear as soon as you enter Crossbone Isle's first screen and exit it. This allows you to fight the Tempest Lizard infinitely and repeatedly, which is not possible with any other boss encounter in either game in the GBA duology. This makes for a good late-game level-grinding method, with every kill giving the party 1360 EXP and 6400 Coins (both increased by 30% whenever slain using an attack-based Venus Djinni as the knockout blow) as well as a guaranteed Potion drop.
There is a second, secret method of reaching Crossbone Isle, taking place much much earlier in the game's campaign, that will only be happened upon by chance by an extremely small percentage of the playerbase if they are not specifically going for it with advance knowledge not provided by the game itself. During the segment of the game where Isaac's party must deal with protecting the Tolbi-bound Ship throughout a perilous crossing west across the Karagol Sea, you will be forced to choose four fellow passengers to fill in for four oarsmen that get injured. After you slay the Kraken boss and choose the fourth substitute rower, the game will check whether the two rowers on the left (the first and third picks) are stronger than the two rowers on the right (the second and fourth picks) by a very specific amount. If this is the case, the ship will be shown veering off course in a northwesterly direction and eventually beach itself against the east coast of Crossbone Isle. One configuration of rowers that qualifies for this scenario is to pick the black-haired bald man, then the blonde lady, then the purple-dressed tour guide, and finally the white-haired old man, in that order.
On the ship, talk to Sean and Ouranos and agree to "check out the island and see if there are any monsters." Once you step into the overworld, you can step back on the ship at any time and answer "Yes" to Sean's question on whether you explored the island thoroughly, which will forcibly resume the ship's voyage to Tolbi Docks. Answering "No" instead will hold off on this happening, allowing Isaac to explore Crossbone Isle some more.
Walkthrough
Crossbone Isle Cave is a dungeon with a rigidly defined layout that will end up blocking your party with obstacles depending on how much of the remaining campaign you have yet to complete and whether you have cleared certain side locations. Beneath the surface-level exterior screen with the cave entrance are nine floors connected by a long sequence of stairs, with a complex puzzle room located on the other side of a shut doorway for that floor. When you attempt to press against the doorway to a new floor's puzzle room for the first time, you will immediately initiate a special battle with a pre-determined set of monsters for that floor, which will always include uniquely colored, vaguely "boss-like" variants of established monster types. Once you have cleared a puzzle room and taken that room's southwest exit back into the stairwell outside, you can push an earth pillar into a gap to permanently unlock a shortcut, making it easy to descend further along the stairs on future visits without having to revisit the adjoining puzzle rooms.
If the early Tolbi-bound-Ship-based method of accessing Crossbone Isle is taken, the party's Psynergy capabilities will only be developed enough that you can clear the first three floors and enter the fourth floor's puzzle room after defeating the "sub-bosses" guarding it. Both the monsters guarding the first four floors' doors and the equipment collected from the first three floors will be on curve with the party's statistics at that earlier point in the game.
By the time you can first "officially" arrive at Crossbone Isle via the Tempest Lizard method at Suhalla Desert, you still will not be able to pass the fourth floor's puzzle room if you neglected to pick up the Cloak Ball from Babi's Palace at Tolbi after the Colosso sequence. Once you come here with the Cloak Psynergy, you will be able to proceed as far as past the sub-bosses guarding the 7th floor (but at least two significant collectables along the way cannot be picked up unless you have also found the Halt Gem in the optional Vale Cave dungeon). From here, your capacity to clear the remaining floors and reach the furthest depths of the dungeon will be unlocked as soon as you gain the Carry Stone in the earlier "one-way-exit-out" portion of Venus Lighthouse fairly shortly beyond Suhalla Desert.
In the final area of Crossbone Isle, labeled in the in-game save menu as the "Pirate Ship" (Japanese: かいぞく船 Pirate Ship), you will end up battling the extra-difficult optional boss Deadbeard. Your primary reward for managing this feat will be the Demon Mail. If this game file ends up being used as the basis of a Clear Data save file and at least so much as a Bronze Password is used with the data transfer system to enhance a game file of Golden Sun: The Lost Age, then having completed Crossbone Isle will also unlock an incidental bonus cutscene in the second floor of Alhafra's inn. The cutscene will become available once the Burst Psynergy has been used to destroy the boulder pinning down the mast of the town's sailing ship.
Exterior screen
When you step into the grass-covered puzzle screen making up Crossbone Isle's sole outdoors portion, walk left of the left horizontal log and temporarily change your classes if necessary to give yourself the Growth Psynergy, and cast it on both the fidgeting sapling and the two saplings above that to climb up the cliff. You can cast Catch to retrieve the nut dangling on the tree atop the cliff.
Slide down the right cliff slide to reach the southeast chest behind the east horizontal log, containing one of the game's four Mints, then climb back up using the three vines. You can slide down the middle cliff slide if you want, though the upper-left chest in this screen only contains a single Coin. The left cliff slide will cause you to drop next to a bush embedded in a wall behind the left horizontal log, and casting Whirlwind (or Gale on it will permanently expose the cave behind it. Whenever you wish to make a future visit to Crossbone Isle, you will have to make the three left saplings grow into vines and drop down next to the cave entrance because of the horizontal log blocking it.
If you have just come to Crossbone Isle through the Tolbi-bound Ship method, your PP reserves will likely be depleted from the Kraken boss fight you would have fought a short time earlier. All areas and screens both outside and inside Crossbone Isle cause the party's PP to passively regenerate as though they were monster-filled areas, even though no random encounters actually take place.
1st Floor: Platform maze
Head down the stairs inside Crossbone Isle Cave until you reach the door to the first puzzle room. Attempt to open it and fight the Hobgoblin and two Viragos, which should be easy even if you come here earlier through the Tolbi-bound Ship method. You will win a Lucky Medal and access to the puzzle room past the door.
The room is a large platform maze above a black abyss, with multiple three-tile-wide platforms with four earth pillars standing on them. Walk counter-clockwise along the perimeter of the room to reach the chest at the north edge of the room, which contains an Antidote. This is a room that will require multiple puzzle resets by leaving and entering the room, as evidenced by how hopping up to the south earth pillar and casting the Move Psynergy to remotely move it off to the left will let you collect the southeast chest with the Nut but lock you off from progressing any further into the puzzle.
After a puzzle reset, hop to the same lower earth pillar and move it one tile right instead, which will allow you to hop west to the lower-left chest and claim 111 Coins. For the earth pillar north of this chest, moving it off to the right will cause you to reach the northwest chest, which contains one of the game's five Hard Nuts — but you will again be blocked from going any further into the puzzle. Perform another puzzle reset.
Once more move the lower earth pillar right, and now move the second earth pillar from the bottom over to the left. Hop northeast below the second earth pillar from the top and move it off to the right. Hop left and up from that to end up just right of the topmost earth pillar, position yourself at the left edge of that pillar's platform, and remotely Move it one tile right. Now hop clockwise across the many platforms near the upper and right perimeters of the black abyss until you can hop back left of the second earth pillar from the top. Position yourself underneath the top earth pillar and remotely Move it one space right, and you can now reach the exit at the bottom-left edge of the room.
Right in front of you outside the exit in the stairwell screen is a chest that will reveal itself to be a Mimic once interacted with. It will drop a Potion upon defeat. Now drop the earth pillar into the gap to your right to create a shortcut that will let you skip going through this puzzle room on future visits to Crossbone Isle Cave.
2nd Floor: Rolling pillars
The door to the second puzzle floor is guarded by what will be revealed as the Succubus and two Grislys. You will win one Potion and one Crystal Powder from them.
The puzzle room does not require any Psynergy to pass and fully loot. Open the chest in front of you to find an Elixir, then open the chest northeast of that to find 222 Coins, and finally open the chest at the northeast corner to find one of the game's four Lucky Peppers. Roll the vertical stone pillar left of that chest over to the left, then roll the horizontal pillar near the coin chest north, and then roll the horizontal pillar above the bottom chest north. This will let you roll the vertical pillar just left of the bottom chest right, then roll the final horizontal pillar at the upper left north. Open the last chest to find the Mystery Blade, a weapon with stats on curve with parties that use the Tolbi-bound Ship method to reach Crossbone Isle early. Open the earth pillar-based shortcut back outside the room, and proceed downstairs to the third floor.
3rd Floor: Platform and key maze
The guardians of the third floor's puzzle room door are revealed to be a Lich and two Fiendish Ghouls. You will win one Psy Crystal from them.
You will be faced with another black abyss with a maze of platforms jutting out of it. Unlike the puzzle in the first room, the objective is to retrieve the colored keys scattered throughout the maze and use them on the doorways lining the north edge of the room, with one hidden red key being needed to take the left exit out. You will need the inventory space open for each of these five keys. Since none of these keys are located on pillars with adjacent tiles you can jump onto, you will have to position yourself on a platform exactly three tiles away from a given key-bearing platform in an applicable compass direction and cast Catch to remotely retrieve it. For example, head to the tile that juts out from the upper-right corner of your starting area and cast Catch to remotely gain the southwest blue key just north of you.
Hop east from the starting point three platforms to reach a branch heading south and north. Hop north twice between two other keys off to your sides so that you can Catch the north blue key off its platform. Return to the branch and take the south branch, hopping to the chamber's southeast corner and then hopping back left from it so you can remotely Catch the lower-right blue key from east of it.
Return to the start point, hop onto the two-tile-tall platform above it, hop left of it, and hop up the straight trail of platforms running along the left edge of the abyss. Around the midway point, you can hop in a northeasterly direction until you position yourself three tiles worth of space above the remaining blue key in the center of the maze and remotely Catch that from above. Return to the left, narrow trail and follow it to the upper edge of the chamber, where touching each of the four blue doors automatically consumes one of the blue keys in your inventory to give you access to the chest behind it. In order from left to right, the four chests contain 333 Coins, the Fairy Ring, one of the game's four Cookies, and a Smoke Bomb.
Directly underneath the rightmost blue door is the top platform of a ring of eight platforms situated around what appears to be an abyss. Hop onto the topmost platform of this ring and cast the Reveal Psynergy to make a platform with the Red Key materialize, and cast Catch to retrieve it while the Reveal effect is ongoing. Now hop back down the left trail of platforms so that you can hop to the red door left of them and automatically use up the Red Key to open it, letting you proceed to the exit.
4th Floor: Shadow maze
The boss-like encounter situated at the fourth floor's puzzle room door is with a pair of Gryphons, which are easily tougher than the previous three floors' guardians. Their relative difficulty will leave an especially strong impression if you have come to Crossbone Isle via the earlier Tolbi-bound Ship sequence, especially if your resources are drained from fighting the previous sub-bosses and the Kraken boss from earlier. They will drop a Potion when felled.
The puzzle chamber is shrouded in a darkness that is illuminated in certain spots by wall-mounted torches, with the bottom two pink statues forcefully realigning themselves in front of Isaac's position wherever he walks on the horizontal beige floor patterns in front of them, and the other statues in the chamber will outright push Isaac off the vertical floor patterns underneath them. Because passing these statues will require the player to have collected the Cloak Psynergy from Babi's Palace in Tolbi later in the game, this room will prevent Isaac from descending further if he arrived here from the potential Tolbi-bound Ship detour, forcing you to return to the ship and resume the voyage to Tolbi. Even so, if you have found the Halt Gem in the optional dungeon Vale Cave, you can cast Halt on the lower left statue while it is moved off to the side so that you can grab the contents of the chest just past it in the shadows, which is a Sleep Bomb.
At any rate, if you have both the Halt and Cloak Psynergies when you reach this chamber during a visit to Crossbone Isle late in the game, you can cast Halt on the lower-right pink statue so that you can enter the shadowed area just past it, below the pink statue that pushes you off the vertical beige floor pattern. Cast Cloak to walk northwest past this statue in the darkness without it reacting to you, and hug the northwest to find a chest in the northwest corner containing 444 Coins. Now head east through the gap in between the blocks to reach the lit-up northeast pink statue above three vertical floor patterns. Keep yourself cloaked as you step into the sole pattern on the left end that is covered in shadow, then walk straight up from it; by the time Isaac unavoidably materializes, he will be too far above the statue for it to attempt to push him back down. This will let you reach the chest containing the Storm Gear, easily one of the best pieces of armor not just for this game but also for Golden Sun: The Lost Age if this is transferred over.
Using the Cloak Psynergy in the shadows just underneath the northwest pink statue to walk past it without setting it off is all you need to reach the southwest corner of the screen. Right next to the exit is a chest containing a Psy Crystal.
5th Floor: Dam and logs
The fifth floor is the first of the "late-game-exclusive" floors, and the scripted battle at the front door with the Lizard King, a Harridan, and two Stone Soldiers will reflect that with the comparatively superior statistics exhibited by the Lizard King itself. The Lizard King will drop a Psy Crystal when felled.
The fifth floor's puzzle chamber operates on the same mechanics and premise as a dam-based puzzle seen much earlier in the game at Kolima Forest, but on a larger scale. Travel along the eastern perimeter of the area and open a chest at the northeast corner containing 555 Coins, then head down the stairs. Roll the lower vertical log left to allow the horizontal log just above that to be rolled down to connect to the lower-left horizontal log near the enclosed chest. Then roll the upper-right vertical log down so that the lower-left vertical log can be rolled back right to stop at its original position instead of against the lower-right rock. Roll the lower-right vertical log back up to complete an orderly-looking path of logs headed west, south, and west to the chest. Flip the gray switch at the bottom end of the chamber to fill the lake with green water, and now hop along the winding trail of floating logs to reach the enclosed southwest chest and claim its Ninja Garb.
Performing a puzzle reset by exiting and reentering the room is recommended to save some time setting up the next solutions. Go back into the now-empty lake and roll the upper-left vertical log left, then roll the horizontal log just underneath that upward this time, before rolling the vertical log back right to its original position. Flipping the switch with this log configuration will result in a trail letting Isaac hop to the north chest, which contains a Lucky Medal. Go back to the switch and flip it to empty the lake, and now roll the northwest log down one tile worth of space. Flip the switch again and the resulting path will allow you to hop to the west end of the chamber, where there is a chest with a Potion. Follow along to the exit at the southwest corner.
6th Floor: Earth pillar maze
The sub-boss battle set up at the entrance to the sixth floor's puzzle chamber is a pair of extra-large Chimeras, which collectively reward you with one Potion when both are felled.
The puzzle chamber is a rather elaborate maze with several earth pillars strewn about the various ledges. Before doing anything else, head north and push the earth pillar with the chest on it up into the gap directly north of it. Cast Move on the two lower-right pillars so that you can hop left across them and walk north from the left pillar, and open the chest along your route to get an Elixir. Follow along down and up two separate wall ladders in order to get onto the narrow ledge running along the north and west perimeters of the area, and head left until you see a Venus Djinni jump down to left of the northwest earth pillar. Continue along the left edge of the chamber to get to the left, especially highly elevated earth pillar, and push it off the wall slide and then slide off yourself to land onto the earth pillar.
Cast Frost on the puddle right of the earth pillar so that you can hop from the earth pillar onto the ice pillar and walk north along the ledge, and open a chest containing 666 Coins. Continue north to watch the Venus Djinni leap back up and run off the far right edge of the screen, apparently slamming against a wall. Push the northwest earth pillar into the gap right of it, then Move it to the right so that it aligns with the tall wall ladder behind it. Climb up to the top level and down this wall ladder so that you step onto the earth pillar, and hop left to open the chest atop the center earth pillar you slotted in here earlier; it contains the cursed Demon Axe.
To get to the south chest in the chamber, go back down to the earth and ice pillars and Move the earth pillar until it stands just below the right of the two blocks flanking the ice pillar. From above the right block, remotely Move the earth pillar one tile right and one tile up. Now climb only one of the two wall ladders at the upper left corner of the chamber and walk south past the opened west chest, and use the two pillars to reach the south chest, which contains a Water of Life.
Presuming you have the Halt Psynergy from Vale Cave, retrace your steps back to the northwest corner of the screen, climb up, and follow along where the Venus Djinni flew off to, and you will watch it flee south. Follow it south to get to a point where you can climb up the ladder south of its new position, and the Djinni will now try to avoid you using the three blocks like the Jupiter Djinni did in Vale Cave. Cast Halt on the Venus Djinni while directly facing toward it vertically to make it stop in place so that you can interact with it and pick it up without a battle, adding the Venus Djinni Bane to your collection. To leave the chamber, climb all the way to the elevated perimeter at the north and west edges of the chamber and slide down the left wall slide again.
7th Floor: Carry block maze
The boss-like enemies guarding the door to the seventh floor's puzzle chamber are a pair of Earth Lizards, which drop a Water of Life when defeated.
The pit-filled cave-like chamber in this floor will require at least one puzzle reset to get all of the treasures at its north end. For this first pass-through, follow along northeast and then northwest to find the upper of two "Carry" cubes, which can only be manipulated meaningfully with the utility Psynergy bestowed by the Carry Stone in the early, "one-way-exit-out" portion of Venus Lighthouse. Move it to the corner northeast of its starting point, then cast Carry on it and drop it up into the gap just above it so you can hop right from it and reach the upper-right chest with the Lucky Medal.
From the "intersection" southwest of the Lucky Medal chest, head south and hop to the lower Carry cube and push it so that it aligns with the right part of gap left of the wall ladder, and Carry it up into the gap (be sure you don't accidentally push it into the pit left of it) so you can hop left across it and reach the southwest exit. Before you step out through the exit, hop to the partially concealed tile of space just underneath the bottom chest to open it for 777 Coins.
When you're done setting up the usual shortcut in the stairs outside, return to the chamber through its right entrance and return to the upper Carry cube. Push it against the brown ledge resembling a very thick "T" and Carry it onto its left edge. Climb up and down the two wall ladders northwest of this ledge to get onto it and Move the Carry cube off into the space left of the "T", and position it in the middle of the space between the "T" and the narrow, winding ledge connecting to the center chest so that you can hop left across the Carry cube. The chest contains the especially useful Wicked Mace.
It is possible to reuse this Carry block to get to the upper-left chest without performing another puzzle reset. Move and Carry it onto the "T" once more (so long as you do not drop it directly in front of the smaller of the two upper-right wall ladders), then Move it so you can Carry and deposit it into the right space of the two-space gap leading to the chest. That way, you can hop onto a tile directly adjacent to the chest and open it for a Psy Crystal.
8th Floor: Dragon statue maze
Owing to the fact you can only reach the door to the eighth floor's puzzle room after using the Carry Psynergy to solve the seventh floor, the boss-like encounter guarding the door is even more difficult than the previous three. These consist of the unique Poison Toad flanked by two Thunder Lizards, enemies otherwise only encountered in the final mandatory dungeon in the game, the later reaches of Venus Lighthouse. Like with all the other "sub-bosses" in Crossbone Isle, the high but otherwise imperfect Luck rating of the Poison Toad still allows it to be susceptible to status conditions like Poison and Stun, so it might be worth unleashing the Venus Djinni Bane against it. When slain, the Poison Toad drops a Water of Life.
Floor 8's puzzle chamber is also similar in premise to Floor 6's in that every element of the maze can be completed through as little as one well-considered pass-through. First-time players are more likely to require a puzzle reset or two because it takes trial-and-error to work out that casting Frost on the puddle underneath the white platform south of the dragon statue causes it to emit hot steam to its left; if the puddle left of the dragon is currently an ice pillar, the dragon's steam will melt it back into the form of a puddle. It will take exiting and reentering the chamber to make the ice pillar underneath the white platform return to the state of a puddle, allowing the dragon to emit hot steam again.
Hop over the puddle left of the dragon statue and cast Frost on it from the north to turn it into an ice pillar, then climb the wall ladder and hop left from it to the two chests. Open the upper chest for 888 Coins, then head down to the west area of the chamber and move the gray stone underneath the two log pillars all the way to the right. Hop over the left puddle and cast Frost on that form the north, then hop left across it to get to the chest at the west end, which contains a Potion.
Hop and head back east to the dragon statue, slide down from under the dragon statue, and cast Frost on the puddle underneath the white platform to raise the platform and trigger the dragon in to melting the ice pillar left of it. Roll the lower of the two log pillars down one tile, then hop over the puddle and once again cast Frost on that. Climb up to the dragon statue again and hop right from the now-raised white platform to get to the chest with a Smoke Bomb. Be careful not to slide down the cliff slide as you return to above the two chest in the center.
Now drop down one of the two left wall slides and roll the upper of the two log pillars down, allowing you to climb up to the remaining closed chest in the center and open it to gain the unique Cleric's Ring — an item that allows one Adept to equip cursed gear like the Wicked Mace without fearing the potentiality that they will be unable to act in a given turn. Transferring this item into Golden Sun: The Lost Age is highly recommended because that game does not offer a Cleric's Ring or a similar effect of its own. Head out the southwest exit.
9th Floor: Log-riding across lakes
The door leading to the ninth and final puzzle room chamber in Crossbone Isle is fittingly guarded by the toughest sub-boss encounter in this series of such encounters: a pair of Cerebuses. It is worth opening the battle with a Meteor summon to make it go by more quickly. You will win a Psy Crystal for defeating the beasts.
You will end up with access to the east of two green lakes where you can ride rolling logs across the water. First, head to the upper-right corner of the lake and ride the upper-right vertical log left so you can hop north to a chest containing a Sleep Bomb. Now rude the lower-left horizontal log all the way up, then ride the vertical log you bump into all the way right. Then, ride the lower-right horizontal log all the way up, then hop right and roll the left of the two vertical logs now in the upper-right corner one tile left so that you can now hop onto the middle vertical log a short ways away from the right edge of the lake. Ride it to the right so that you can ride the lower-right log left to the square island in the lake with a chest containing 999 Coins. Once you return to the east edge of the lake, ride the middle vertical log all the way west.
In the middle of the two lakes in this chamber is a chest containing a Water of Life. The left lake features a particularly tricky but optional log-riding puzzle above the chamber's southwest exit. First, take the time riding all three of the horizontal logs at the south edge of the lake all the way north. Then, ride the lower-right vertical log west so that it stops against the left horizontal log, then ride the center horizontal log back down so that it bumps against the lower vertical log. This will let you ride the middle vertical log left, then ride the right horizontal log down, and finally ride the top vertical log left so you can hop into a chest's enclosed space at the top of the screen and claim the cursed Muramasa.
10th Floor: Pirate Ship
Now that you have all nine chambers' exterior shortcuts established, you can freely travel between the surface level of Crossbone Isle and the lowest area of Crossbone Isle Cave: a run-down, heavily damaged ship the game's save menus refer to as the "Pirate Ship." Saving here is indeed highly recommended, and not just because the strongest Mimic in the game lies just nearby (which rewards you with another Potion once it is felled). After you hop across the broken-off gaps of the ship deck, while you walk up the left of the two staircases, you will be thrust into a battle with the optional boss Deadbeard — a very dangerous and durable enemy on par with the game's final boss. If you manage to defeat it, you will get a healthy payout of EXP and Coins and a Water of Life drop, and a chest will have materialized that will contain the cursed Demon Mail. You are free to leave Crossbone Isle after this.
Enemies
| Bestiary of Crossbone Isle (Surface) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Tempest Lizard (boss) | 28 | 3000 | 295 | 94 | 114 | 1360 | 6400 | 1/1 | ||
| Bestiary of Crossbone Isle (Level 1) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Hobgoblin (unique) | 23 | 650 | 203 | 54 | 65 | 223 | 800 | 1/1 | ||
| Virago (2) | 17 | 185 | 199 | 47 | 89 | 87 | 120 | 1/16 | ||
| Mimic (unique) | 23 | 729 | 214 | 59 | 97 | 347 | 386 | 1/1 | ||
| Bestiary of Crossbone Isle (Level 2) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Grisly (2) (unique) | 23 | 800 | 208 | 63 | 78 | 243 | 700 | 1/1 | ||
| Succubus (unique) | 17 | 529 | 195 | 49 | 101 | 101 | 143 | 1/16 | ||
| Bestiary of Crossbone Isle (Level 3) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Fiendish Ghoul (2) (unique) | 17 | 609 | 199 | 45 | 69 | 87 | 109 | 1/16 | ||
| Lich (unique) | 23 | 900 | 192 | 48 | 106 | 263 | 1200 | 1/1 | ||
| Bestiary of Crossbone Isle (Level 4) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Gryphon (2) (unique) | 23 | 1100 | 213 | 56 | 98 | 303 | 1900 | 1/1 | ||
| Bestiary of Crossbone Isle (Level 5) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Lizard King (unique) | 28 | 2000 | 285 | 93 | 92 | 535 | 1200 | 1/1 | ||
| Harridan | 22 | 231 | 261 | 66 | 118 | 150 | 164 | 1/32 | ||
| Stone Soldier (2) | 22 | 179 | 241 | 105 | 104 | 98 | 98 | 1/32 | ||
| Bestiary of Crossbone Isle (Level 6) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Chimera (2) (unique) | 28 | 1350 | 294 | 90 | 121 | 465 | 800 | 1/1 | ||
| Bestiary of Crossbone Isle (Level 7) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Earth Lizard (2) (unique) | 28 | 1550 | 278 | 97 | 102 | 545 | 920 | 1/1 | ||
| Bestiary of Crossbone Isle (Level 8) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Poison Toad (unique) | 34 | 2250 | 363 | 97 | 93 | 1732 | 2200 | 1/1 | ||
| Thunder Lizard | 28 | 456 | 347 | 133 | 134 | 422 | 221 | 1/128 | ||
| Bestiary of Crossbone Isle (Level 9) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Cerebus (2) (unique) | 35 | 2200 | 369 | 130 | 151 | 1863 | 3200 | 1/1 | ||
| Bestiary of Crossbone Isle (Pirate Ship) | ||||||||||
| Monster Name | LVL | HP | ATK | DEF | AGI | EXP | Coins | Weakness | Drop | Drop Rate |
| Mimic (unique) | 30 | 1206 | 367 | 126 | 167 | 1009 | 643 | 1/1 | ||
| Deadbeard (boss) | 43 | 6000 | 468 | 178 | 180 | 8000 | 9000 | 1/1 | ||
Note: The Tempest Lizard will not appear at the time you reach Crossbone Isle by the Tolbi-bound Ship.
Items
Exterior-level screen
1 Coin: Found by climbing to the top of the cliff and taking the middle dirt slide.
Mint: Found by climbing to the top of the cliff and taking the rightmost dirt slide.
Nut: Dangling off an elevated tree. Use Catch to get it.
1st Floor
Antidote: The easiest item to get on this floor. To reach it, simply take the path to the right upon entering the room.
Hard Nut: This item can only be obtained by making the rest of the room inaccessible. Cast Move on the second stone and move it to the left.
2nd Floor
Elixir: Found in the treasure chest directly in front of the entrance.
Lucky Pepper: Contained within a treasure chest in the top right corner of the room.
Mystery Blade: Found in the treasure chest blocked by the final rolling pillar.
3rd Floor
4 Blue Keys: Found in various locations throughout the room. The only way to obtain them is by using Catch. They are used up to collect the following four items:
Cookie: Found behind the middle-right blue door.
Fairy Ring: Found behind the middle-left blue door.
Smoke Bomb: Found behind the leftmost blue door.
Red Key: Located in the center of a ring of platforms on the right side of the room. Cast Reveal to see the key, and cast Catch from the top platform in the ring to obtain it.
4th Floor
Psy Crystal: Waiting in a treasure chest by the room's exit.
Sleep Bomb: Cast Halt on the first moving statue to the right of the entrance.
Storm Gear: Found near the top of the room, on the right side. This chest requires players to pass all three moving statues.
5th Floor
Lucky Medal: Located on the left side of the room, parallel to the chest containing the 555 coins.
Ninja Garb: Located on the left side of the room, near the bottom of the room. Players cannot reach this chest and get to the exit of the room at the same time.
Potion: Contained within the only treasure chest on the left side of the room that can be opened on the way to the exit.
6th Floor
Bane: This Venus Djinni is chased through the sixth floor at several points and will eventually require Halt to obtain. It does not need to be fought.
Demon Axe: Located in the chest resting on a movable earth pillar in the center of the room. The earth pillar must first be moved further up before the chest can be accessed.
Water of Life: Contained in the chest near the bottom of the room.
7th Floor
Wicked Mace: Contained in the bottom left chest in the Carry stone puzzle at the top of the room.
8th Floor
Cleric's Ring: Located in the bottom chest of the two chests in the center of the room.
Level 9
Muramasa: Waiting above the left lake.
Pirate Ship
Demon Mail: Found in a treasure chest that materializes after defeating Deadbeard.
History
Though Crossbone Isle does not play a role in the main plot of Golden Sun, there is some in-universe awareness of its existence expressed in not only the first game but The Lost Age as well. Some across Weyard have heard rumors that an uncharted island lies in the Karagol Sea and contains all manner of hidden treasure, and certain circles among pirates the world over desire to get this treasure for themselves. The island itself, apparently located within the Karagol's northwestern sector, contains an ancient complex of man-made chambers apparently designed to test the Psynergy capabilities of intruders. Moored at the bottom of this complex is an ancient and broken-down "pirate ship" haunted by "Deadbeard", a ghostly entity of horrifying power.
During Golden Sun, Isaac's party takes the ferry service running between Kalay Docks at the east end of the Karagol and Tolbi Docks at the west end. Over the course of the particularly troubled voyage, the party and other warriors such as Sean and Ouranos are unable to prevent several oarsmen from getting injured by sea monsters apparently driven mad by the recent eruption of Mt. Aleph. Isaac is forced to designate specific tourists riding the ferry to take the place of the downed oarsmen, all of whom have varying degrees of forearm and back strength suited for the job. If Isaac's choices for the replacement oarsmen result in those rowing on the starboard side being significantly weaker than those on the port side, the ship will veer off course to the northwest and head toward the unfamiliar island, and the ship's captain and his assistant, Kaja, will have to temporarily anchor the ship at the east coast of Crossbone Isle and regain their bearings.
Though the passengers' nerves have been frayed by the constant attacks from sea monsters, the tour organizers cannot let them step ashore onto an unknown island potentially teeming with monsters of its own and asks the warriors to scout the island. Sean and Ouranos, who had previously promised to protect the ship itself, ask Isaac's party to head out in their stead. Isaac's party may discover the ancient dungeon underneath the isle and make some headway regarding its traps and exotic monsters, but their Psynergy abilities will ultimately be insufficient to get particularly deep. By the time the party returns to the ship, whether or not they affirm there are monsters on the island, the ship's crew will have finished re-plotting their course back to Tolbi, and the ship hastily shoves off.
Regardless of whether any of the above takes place during Isaac's journey canonically, his party may eventually discover another way onto Crossbone Isle by being violently transported there via one of the powerful tornado-spewing lizards native to Suhalla Desert. By that point shortly before their arrival at Venus Lighthouse, they will have developed their Psynergy and combat skills to such an extent that they actually are capable of managing the feat of solving every one of its ancient riddles, besting every monster, and looting every treasure stored inside the complex. They may even come face to face with Deadbeard itself and slay the towering and seemingly corporeal skeletal entity. Once Isaac is done with this detour, the party may bring themselves back to the mainland via the same tornado-riding trick.
Despite this potential sidequest apparently taking place without Isaac's party bothering to notify any other individual or group about it, certain modern-day pirates will somehow catch wind of the fact that the island in the Karagol rumored to have buried treasure has had all of its treasure picked clean, and that the "ancient ghost pirate" defending it was even slain. The pirates somehow even become aware that it was someone named "Isaac" who managed the feat.
Therefore, at any point in Golden Sun: The Lost Age following an incident in the distant town of Alhafra where its ship gets stolen, the traveling party of Adepts led by Felix may happen upon a pair of gossiping pirates in the second floor of the inn, where they talk about how someone named Isaac picked Crossbone Isle clean. These pirates apparently ascribe to a code that holds that this "Isaac" would be their leader by default because of that achievement, and they head out the inn in hopes of searching for Isaac's "pirate crew" to join. This conversation can take place late enough in the game that Isaac's traveling party of Adepts may have already joined forces with Felix's, in which case the pirates will be unaware that they are ironically passing by the person they're setting out to search for. Regardless of whether this conversation is seen, nothing comes of this incidental thread throughout the remainder of The Lost Age, and there is no mention in Golden Sun: Dark Dawn of Isaac having gained any followers among piratekind over the 30 years since, even as he gains worldwide notoriety of a different sort.
Trivia
- The music that plays on the Pirate Ship segment in the furthest depths of Crossbone Isle Cave is the "villains' theme" heard whenever antagonists Saturos and Menardi make an appearance.
- In a minor graphical bug, the swirling pink tornado provided by the Tempest Lizard can be made to lose its transparency as it remains standing on the northwest beach. If you bring up the Djinn, Item, or Status menu screens and then exit out of them while in the overworld segment of Crossbone Isle's surface, the tornado will suddenly become fully opaque (failing to rapidly toggle between disappearing and reappearing with every single frame). This does not happen if you bring up the Psynergy menu and then come out of it. It regains its transparency once you enter the Crossbone Isle location nearby and then head back out.
- Crossbone Isle is portrayed as located in the Karagol Sea, but the in-game sea would be far too small to contain the island without being visible from along the sea's shorelines. The part of the overworld map containing a version of Crossbone Isle sized up to more realistic proportions is located far to the west of the explorable overworld, which is true in both Golden Sun and The Lost Age even though it cannot be reached in the latter game. In the first game's code, it is located far to the west of Imil, and in the second game, it has been moved far to the west of Prox. Seeing this phenomenon for oneself requires using external hacking hardware such as Action Replay or Code Breaker Advance and turning on some kind of walk-through-walls code.
