Hidden Dungeon

The Hidden Dungeon, also known as The Ultimate Dungeon or ??????, is an optional post-game dungeon located in the Crystal Tower in Grymoire in the Maxima version of World of Final Fantasy.

The Hidden Dungeon becomes available after clearing all four of the EX dungeons in The Girl's Tearoom. On the seventh floor of the Crystal Tower, a purple gate that was not there before appears, and entering through this gate leads to the Hidden Dungeon.

Navigation
As with the EX dungeons, the Hidden Dungeon consists of portions of previous dungeons in Grymoire. The first room in the dungeon is a simulacrum of the Watchplains's Backroad 1. At the end of the area are four Warp Crystals, each taking the player through a route consisting of two areas then a boss fight at the end with one of the Four Fiends from Final Fantasy. Defeating a boss unlocks a route, and all four routes must be cleared to unlock the final route.

Clearing just one route creates an Exit Gate in the center of the four Warp Crystals. A hidden white Warp Crystal near the dungeon's entrance can be used to travel close to this hub.

When navigating through a route, the player must use black Warp Crystals to proceed to the next floor. If a room has two, the player must touch the correct one to proceed. Choosing the wrong one takes the player to a simulacrum of the Phantom Sands's Toil 6, and the Warp Crystal there takes the player back to the beginning of the dungeon where they must traverse through the route again. Choosing the correct Warp Crystals eventually takes the player to a simulacrum of the Watchplains's Backroad 3, where they must traverse all the way to the Warp Crystal that takes them to the boss room.

After defeating the boss at the end of a route, they receive a high-tier battle item that corresponds to the element of the boss they just defeated, a Half Mega-Potion or Half Mega-Ether, and even a prismarium of one of the bosses. Defeating the boss also clears the route, indicated by the Warp Crystal in the first floor gaining color.

Once all four routes are cleared, a black Warp Crystal appears behind the Exit Gate in the first room, and gives the player access to the final route of the dungeon. In the final boss room is the only Save Crystal in the dungeon, and a boss fight with Garland and all Four Fiends.

Treasures

 * Reward items
 * Earth Spellstone, Half Mega-Potion (defeat Lich, Earth route)
 * Fire Spellstone, Half Mega-Ether (defeat Marilith, Fire route)
 * Water Spellstone, Half Mega-Ether (defeat Kraken, Water route)
 * Wind Spellstone, Half Mega-Ether (defeat Tiamat, Wind route)
 * Megalixir, Mega-Potion, Elixir (defeat Garland and all Four Fiends, final route)


 * Prismariums
 * Lich prismarium (defeat Lich, Earth route)
 * Marilith prismarium (defeat Marilith, Fire route)
 * Garland prismarium (defeat Garland and all Four Fiends, final route)

Watchplains rooms

 * Watchplains 1
 * Mandragora (x3)
 * Goblin Guard, Goblin (x2)


 * Watchplains 3
 * Coeurl (x2)
 * (x2)
 * (x2)

Earth route

 * Nether Nebula room


 * Train Graveyard room


 * Boss room
 * Lich (Boss)

Fire route

 * Valley Seven room


 * Pyreglow Forest room


 * Boss room
 * Marilith (Boss)

Water route

 * Sunken Temple room


 * Saronia Docks room
 * Sharqual,


 * Boss room
 * Kraken (Boss)

Wind route

 * Dragon Scars room
 * Wind Toad (x3)
 * Sylphine, Memecoleous (x2)
 * Cocodrille (x3)


 * Crystal Tower room


 * Boss room
 * Tiamat (Boss)

Phantom Sands room

 * Phantom Sands room
 * Coeurl (x2)

Final route

 * Icicle Ridge room


 * Underground Prison room


 * Boss room
 * Garland, Lich, Marilith, Kraken, Tiamat (Bosses)