Warmech(*1)! Reason: Hardness: He is the hardest boss in the game

Chaos(*2)! Reason: Coolness: He is cool looking and have a cool name. Powerfullness: Second most powerfull boss in the game.

Lich(*3)! Reason: Coolness: He's the coolest looking boss in the game.

Tiamat(*4)! Reason: Coolness: Same old reason: Bahamuts twisted twin (even if he doesn't look like it in this game).

Zombie Dragon! Reason: Coolness: He's cool looking and stuff.

Garland! Reason: Coolness: He= Chaos. Powerfullness: He= Chaos.

Vampire! Reason: He is Lichs little friend.

Astos! Reason: BecauszzzzzzzzzzzZZZZZZ

Not as detailed as in FFVIII. But I'm so sleepy rigth now...