Quote Originally Posted by lololink View Post
Except that Ultima is the final boss of the main storyline and have a huge influence in the story while diabolos, siren and fenrir have almost no story except "hey i'm a notorious bad guy that do bad things in a dungeon, comme kill me, i have shinies !!! ( shiny purified water !)
One of the screenshots shows Fenrir in front of Shiva's aetheryte crystal. He clearly has more of a place in the story than just being a dungeon boss.