Quote Originally Posted by Frizze View Post
The story for this raid in this game is that Agrius, Mustadio, and Cid are guarding the sealed tomb that holds Ultima captive(which happens to be beneath the ruins of the Orbonne Monastery). Theyre specifically testing if we're strong enough to defeat her before allowing us to enter. The reasoning being part "not wanting to see more innocents die" and part "if we unseal the tomb she might escape and doom the world". Then when the fight with her starts to get intense, they jump in to help(along with their Ramza) having recognized in us the power to see the fight through to the end.
Yup, and this is an important distinction. It shows that the Auracite can be used with NOBLE intentions, and the results are monstrous, but still good-natured beings, unlike the twisted, selfish, vengeful creatures we'd fought up to that point. The battles against Mustadio, Agrias, and Cidolfus are there to test any who would try to defeat Ultima. Anyone incapable of defeating them would stand no chance against Ultima herself. The flashback cutscenes following Orbonne Monastery show the three of them volunteering to take on that duty, in fact.

It's notable that while Auracite was created by Ultima, the stuff isn't inherently evil. It can be used for good or evil, depending on the nature and intent of the user. Ultima herself, for that matter, is presented more as something incredibly alien, rather than explicitly evil. When first encountered, she attempts to resolve the situation peaceably, with an offering of more Auracite - and seems surprised when we don't gratefully accept. It's not hard to imagine that back in the days when she was worshiped, this was a standard exchange for her.