Enemy list
Chest list
Fly to the Ancient Ruins after finishing the Optional Summons. The Ancients' Maze is the last dungeon before the Crystal Tower, but four overworld bestiary entries need registering first. Interact with the Earth Crystal inside if you want a free heal before heading out to the fields.
Outside the maze
Four new enemies roam the overworld around the maze entrance. Farm them all before going inside.
Death Needles spawn in the wooded areas at 1,350 HP and 91 ATK; Liger and Minotaur roam anywhere at around 1,960-1,990 HP and 107-110 ATK. None of them should cause problems at this level. Aeon is the outlier. It has 3,360 HP and 110 ATK, but the real problem is finding one. It's extremely rare and only appears on open plains, not in forested tiles. If it won't show up after a dozen fights, skip it for now and try again after exiting the maze (there's a better spot on the other side). Once the other three are registered, head inside.
Ancients' Maze
Six new bestiary entries fill the maze, and several of them hit harder than anything you've fought outside of boss encounters.
Greater Demon can summon Iron Claws mid-fight at 3,800 HP, so prioritize it before the adds pile up. Thanatos and Bone Dragon are the tankiest regulars at 4,000 and 4,800 HP respectively; Bone Dragon in particular drops fast to Curaja, which can deal over 9,000 damage since it counts as undead. Keep your party's health high at all times.
And watch for King Behemoth on the deeper floors. It's rare, but 17,000 HP with Meteor at low health makes it a genuine threat. Don't leave it limping; dispatch it as quickly as possible once you commit.
The maze itself is dense. Fifteen chests are scattered across its winding corridors, and the Crystal set (Shield, Mail, Gloves, Helm) found here is the best armor currently available.
Entry area. Go north around the room with the Earth Crystal. At the top of the screen, head east for an Elixir (307/367). Return west and go through the door to enter the maze proper.
First forks. Walk north to the first fork and go north again. Follow the path for a Crystal Shield and Lilith's Kiss (309/367). Backtrack to the fork and take the opposite direction west. At the next fork, go north for Crystal Mail (310/367). Return to the fork, continue west, and when you spot a chest to the right, grab the Black Musk (311/367).
West wall. Continue east, then head north along the west wall of this area until you can't go any further. Go east to find Crystal Gloves (312/367). Head back south to the last split, then east down a long path. When you see a break in the wall to the south, go through it and keep heading south to three chests: Break Blade, Phoenix Down, and Omnirod (315/367).
Four-way fork. Go north from the three chests to reach a four-way intersection. West leads to a Crystal Helm (316/367); east leads to a Dual Haken (317/367). Grab both, then return north to the break in the south wall mentioned earlier. Continue east and follow the undeviating path until you hit another fork.
Deep maze
Northeast maze. At the fork, go south, east, then north to reach a Phoenix Down (318/367). From that chest, go east, north, and east again for a Protect Ring (319/367). The Protect Ring is an extremely valuable accessory; equip it immediately.
Final room. From the Protect Ring chest, go slightly west, then south along the east wall. Follow the long winding path (east, then a long stretch west) until you reach a door. Inside, grab the Holy Lance on the left and Hellish Claws on the right (321/367). That's all fifteen chests.
Exit through the north door to return to the overworld. The Crystal Tower looms ahead.
Confirm your bestiary count and verify 321/367 chests before entering the Crystal Tower. The Holy Lance is a strong Dragoon upgrade that pairs well with Jump, and the Hellish Claws give your Monk or Black Belt raw damage that'll stay relevant through the endgame.