Before we go back to Earth, let's get one of the most powerful summons for Rydia. The cave is in the east; it looks like a ring on the map.
Before you face Bahamut, you'll have to fight 3 Behemoths. The thing about this specific monster is that it only uses physical attacks, and when it gets hit it'll also counter with a physical attack. The trick is to use Blink on everyone before you attack it. Edge can use Mirage, which has the same effect as Blink but can only be cast on himself. Cecil with Excalibur should deal over 2000 damage while FuSoYa can cast Flare. Everyone else can defend to avoid the counterattack.
Bestiary Checklist:
Boss: Bahamut
This boss only knows one attack, Mega Flare, which deals 9999 damage after the countdown.
The trick is pretty easy: both Rosa and FuSoYa cast Reflect on everyone immediately. Everyone else attacks while Rydia casts Leviathan until you win.
Note: Reflect will bounce the Mega Flare back to the boss so you will receive zero damage.
Chests/Items:
- C-299: Genji Gloves - B1, bottom-left chest.
- C-300: Genji Shield - B1, far-right chest.
- C-301: Genji Armor - B2, left chest.
- C-302: Genji Helm - B2, right chest.
Leave the cave using Teleport or backtrack.