Enemy listEnemies
Chest listChests
Tropical Island is a 5-floor maze. The Black Mask sits at the bottom, guarded by a pack of Big Horns. Poison is constant here; almost every fight inflicts it. This chapter has 20 chests, 2 new bestiary entries (4 missable sea enemies), and one boss.
Sailing to Tropical Island
Head back to your ship near Mysidia and sail south. The Tropical Island is a tiny speck near the bottom of the world map; it's easy to miss on the first pass. Werewolves roam the island's overworld but aren't as dangerous as the enemies you fought around Mysidia.
Tropical Island
The dungeon loops up and down across five basement floors in a confusing layout. Poison Toads (300 HP) are the biggest nuisance; they inflict both Poison and Toad status, and Toad disables a party member until cured with Maiden's Kiss or Esuna. Level Esuna before coming here if you haven't already. Yellow Jellies (45 HP, 210 DEF) resist physical attacks completely, so use magic on them. Wild Horns (300 HP, 40 ATK) show up in the monster chests alongside Poison Toads.
B1. Head straight down from the entrance for Chest 1 (Eye Drops). Go back north through the narrow passageway to find Chest 2 (Hi-Potion) at the end. On your way south, there's an opening on the left with Chest 3 (Hi-Potion). Continue left and down for Chest 4 (Ether), then loop to the bottom-left corner for Chest 5 (Spider Silk). Take the northern passageway to the stairs.
B2. Skip the chest directly ahead; you'll grab it on the way back. Go left and descend to B3 where Chest 6 (Spider Silk) sits near the stairs. Continue through B4 until you reach 1F, a tropical settlement with masked villagers. Two merchants sell weapons here, but nothing you can't find cheaper in Mysidia. Head back to B2.

B2. The skipped chest is now Chest 7 (Sleep Grass). Go right for Chest 8 (Scourge Tome), then south to the bottom-right corner for Chest 9 (Blind Tome). Head left for Chest 10 (Scourge Tome) and Chest 11 (Blind Tome); these tomes aren't worth learning but sell for decent Gil. Continue north to B3.
B3. Chest 12 (Garlic) is south of the entrance. Go back north and descend to B4, then take the top-left stairs to B5. Grab Chest 13 (Death Idol) and return to B4. Take the southern fork down to a different B3 staircase. Chest 14 (Phoenix Down) is at the dead end; this one has monsters. Back to B4.
B4. Take the bottom-right stairs to B3, head north to B4, then descend to B5. Chests 15-17 (Gaia Drum, Sleep Grass, Sleep Grass) are clustered together in a corridor; the top-left one is a monster chest with Wild Horns and Poison Toads. Return to B4 and grab Chest 18 (1,000 Gil) on the northern path. Take the right stairs to B5 for Chest 19 (Sleep Tome), then go left into the boss room.
Big Horn x4
Four Big Horns (1,140 HP each, 50 ATK, 50 DEF) guard the Black Mask chest. They only use physical attacks and have no elemental weakness, so Protect is the key defensive spell. Cast it on your party, focus one target at a time, and the fight ends fast. You've likely fought Big Horns on the Mysidia overworld already; four at once just means more incoming damage, not a new threat.

Once the battle is won, open chest 20 to collect the Black Mask. Use the purple floor pad behind the chest to teleport out instantly. And with both masks in hand, the path to the Ultima Tome is almost open.
Sail back to Mysidia to place the Black Mask, then head to the Cave of Mysidia just north of town. The cave is tougher than this dungeon; bring Ethers and make sure your healing magic is leveled.