The Tropical Island
The Tropical Island is a small, easily-missed island in the middle of the southern Ocean. There is nothing to be found here that you need immediately, but the dungeon is filled with valuable Treasures and well-worth exploring. Interestingly enough, by the time you are sent here for plot reasons, the equipment found here will be obsolete, and the Monsters will be trivially easy. All gameplay indications are that you are supposed to explore the Tropical Island immediately after obtaining the ship. You can skip it, but for the purposes of building up skills and gear, I recommend taking it on now.
This is a complex dungeon and you'll likely need to make multiple trips. A Cottage can help you recover between runs, but if you want to save gil, you can head to Salamand to rest. The Snow Field is located directly south of the Tropical Island, so if you head southwest around the mountains, you can dock your ship and trek east to Salamand. It's not a short trip, but the Monsters should prove no challenge once you make landfall.
Tropical Island B1
The Tropical Island introduces a number of new Monsters, though the most common foes on B1 are those you've seen before. Stunners from the Dreadnought appear here in smaller numbers, but alongside the lesser Wererats. The next most common encounter introduces Dual Deads, a frighteningly powerful, Undead variants on the Dual Heads that often accompany them. They have 300 HP and high Defense, so you'll want to exploit the Undead weaknesses to Fire and Cure. This is particularly urgent because they make a whopping five powerful attacks.
Next up are Red Mousses and Yellow Jellies, two slime-type creatures with nigh-impenetrable defense and different Elemental weaknesses. Yellow Jellies are the weaker of the two, and don't always appear. Any Fire or Ice Spell is likely to be enough for even a group of them. Red Mousses are tougher, and are instead vulnerable to Lightning. They absorb Ice but not Fire, so a decent-level Fire Spell is a good way to thin out mixed groups. Both types of Monster cause Poison, and Red Mousses get two attacks in order to do so.
Very rarely, you'll run into 1–4 Poison Toads, tough Monsters with 300 HP, high defense, and three powerful attacks that inflict Poison. Fortunately, they have an exploitable weakness to Ice like most cold-blooded Monsters. This is a rank 4 encounter, one of the first you've seen as a Random Encounter. (Though the encounter with Dual Deads unaccompanied by Dual Heads is rank 5!)
While the Monster variety is limited, the Tropical Island makes up for this lack with its complex layout. There are two main paths to follow, both featuring many side paths with Treasure. One leads to the Black Mask, while the other leads to a small town-like area of creatures wearing masks and selling powerful items. You'll want to fully explore both in order to find everything available here.
The path doesn't split until B2, though there are a number of side paths to investigate on B1. The main path splits in three early on. Continue south for some Eye Drops. The northern path splits in two, and you'll find one Hi-Potion on each branch. The central, western path leads onwards. That branches south, leading to an Ether if you follow the south wall. Back on the main path, continue west and then south to find a valuable Spider's Silk. This Item will cast Slow 9 on all enemies, which will cancel out most Monsters' extra attacks entirely. They are unfortunately quite rare, though. To reach the stairs to B2, head north from the main branch rather than following the path to the Spider's Silk.
Tropical Island B2
The breakdown of Monsters on B2 is largely similar to that of B1, though featuring more frequent encounters with Dual Deads. There are also more Poison Toads to deal with. The only good news is you're less likely to encounter Red Mousses which require Spells to defeat. You'll likely be using a lot of MP either way, though.
The Town
As you follow the path north, you'll notice that this dungeon's graphics are quite busy, often making it difficult to make out the path at all. The western branch up ahead leads to a chest containing Sleepgrass as well as a set of stairs to B3. This path leads to the Tropical Island town, a short path that is worth traveling first. There are no branches on this path, and you'll find a Spider's Silk along the way on B3. Once you reach B5, you'll be in a safe area with a bunch of NPCs.
These odd masked beings mention the Black Mask hidden elsewhere in the dungeon, and one of them runs a Variety Shop with some nice goods. Of particular note are the powerful Demon Spear and the Ruby Cuirass, which serves as the first mage Armor upgrade you've seen in some time. You can also buy Gaia Drums, though they are quite expensive. The Demon Axe is less notable, an expensive upgrade that's only marginally better than the Mythril Axe. Like swords, axes are underwhelming during this stage of the game, and you can benefit greatly from switching a character to using spears for a while.
The Path to the Black Mask
Whether you walk back to B2 or Teleport out and return, you'll find the rest of the dungeon along the eastern branch of the first corridor on the floor. You'll follow a long, spiraling path towards the center of the floor, finding two Blind Tomes and two Scourge Tomes along the way. If you didn't get any from Magicians earlier, this may be your first opportunity to learn Scourge, a fourth (Poison) Elemental attack Spell that is equivalent to the other three, but exploits different Monsters' weaknesses. The first Scourge Tome is in the northeast, just off the beaten path. After turning south, you'll find two more tomes (Blind to the southeast, Scourge to the northwest) along short branches. The final Blind Tome is found on a branch to the southwest of the path to the stairs to B3.
Tropical Island B3
You'll find nothing but tough Monsters on B3. The Stunners and Wererats are gone, replaced with more Poison Toads and other beefy monsters. You'll also occasionally meet Wild Horns, another multi-attacking Monster with 300 HP, albeit one without any Elemental weaknesses. They're rank 5 and can appear in groups as large as 4. If you start running out of resources, don't hesitate to Teleport out and rest up with a Cottage or in Salamand.
The layout of B3 is pretty simple, as it functions as a transitionary floor. There are four distinct sub areas. One is on the path to the town, while the longest is part of the main path to the Black Mask. You can head south from the stairs up to B2 to find Garlic, while the northern path loops around and leads to B4. The other two paths are reached from B4.
Tropical Island B4
The Monsters on B4 are much the same as on B3, though the common encounter with Dual Deads and Dual Heads. has been replaced with a rarer encounter with just 1–5 Dual Deads. What sets this floor apart is that it has no less than 9(!) staircases, leading to both B3 and B5. This can be a very confusing floor to navigate for that reason.
You'll traverse the southwestern part of B4 on your way to the town, but when headed for the Black Mask, you'll start in the center of the floor. There are four paths available, two to the southeast and two to the northwest. All four lead to different treasures.
- If you head directly south from the stairs, you'll find yourself back on B3. There is a Phoenix Down in this hallway, guarded by various types of Undead you've dealt with before. Fire or Cure will take them out quickly.
- The stairs in the southwest corner also lead back to B3, and the start of a long path to three treasure chests. The path returns to a side area of B4 and then to B5. Follow this path west to a set of three chests. The middle chest contains a Gaia Drum and is guarded by a combination of Poison Toads and Wild Horns. The other two chests each contain Sleepgrasses and are not guarded.
- In the northwest corner of the floor, you'll find stairs leading to a tiny part of B5 that holds a Death Idol.
- Head northwest and then back east to find the path to the Black Mask. You can find 1,000 gil in a chest along the way while still on B4.
Tropical Island B5
Almost all the Monsters on B5 are big, tough brutes, but there is one new and interesting foe here: the Changer. Their basic attack is no big deal, but they like to use Swap to exchange HP and MP totals with your party members. With 80 base MP, this can actually serve as a boon for your spellcasters, restoring their MP deep within a dungeon. With only 140 HP, this can also lead to increases to both Stamina and HP.
There are two side paths to treasure on B5, but the Black Mask is reached from the watery central area. There is a Sleep Tome in a chest near the stairs. This Spell works well against Changers, who have a weakness to Mind effects. Your destination on this floor, however, is a small room to the west.
Before you can get your hands on the Black Mask, you'll have to face off with a Big Horn. This monstrosity has over 1,000 HP, high Defense, and four powerful attacks. The Spider's Silk you found may be of help, as are the usual buffs like Blink and Berserk. As with other high-defense foes, inflicting Curse with the Ancient Sword can turn this fight in your favor. There's a teleporter out of the dungeon just beyond the Black Mask, so don't hesitate to go all out.