Chaos Bahamut (Final Fantasy XIII-2 boss)

Chaos Bahamut appears for the first time in Final Fantasy XIII-2 as an Eidolon incarnated by Caius Ballad. Having two appearances in the game, only one is part of the main storyline while the other is part of the pre-game tutorial. This Bahamut is considerably weaker in comparison to the three other hulking Bahamuts that appear in the game, Amber Bahamut, Garnet Bahamut, and Jet Bahamut.

His main appearance in the game is right before the final boss battle in Academia -500 AF-. You will encounter after traveling to the final waypoint in the area.

Strategy
Chaos Bahamut has two forms, the first being his default form where he simply hovers before using Metamorphosis, upon which he becomes a flying mechanical wyvern. In his usual form, he will utilize potentially crippling physical attacks to beat down your party in sets of two. After a small amount of time of back-and-forth with this, he will change between forms and begin to use powerful magic attacks instead. This is when the party must watch out for his ability Megaflare, which cause a large amount of nonelemental damage with a side effect of Wounding the party.

The best way to counter Chaos Bahamut's onslaught of amped-up attacks is to use the all-Sentinel paradigm Tortoise to minimize the effect of Megaflare. It is completely immune to the Sentinel's Provoke ability, meaning you'll have to worry about healing a lot more often. Unless your party is fairly strong, it will be a good idea to a Sentinel in your paradigms to minimize area effect damage.

Naturally, you'll want a good medic or two in one of your paradigms to pick yourself back up when your HP gets down. It might be a good idea to carry a few Wound Potions with you to help eliminate the Wound damage from Megaflare. Since Chaos Bahamut is very suspectible to the three debuffs Deprotect, Deshell, and Imperil, a good Saboteur can take massive advantage of this weakness. Once you boost his Chain Bonus up significantly, it will start taking some massive damage and shouldn't take long to defeat.