Quote Originally Posted by Xenor View Post
Just because Fenrir, Siren and Diabolos are in dungeons doesn't mean they can't be used again. Ultima Weapon is a good example of one that was.
It does mean that technically. They can be used again but for what purpose? They're originally summons - in XIV would make them Primals. Which primals were used as dungeon boss before becoming a primal fight? Ultima is a good example simply because it's TECHNICALLY a primal as well and didn't have a proper fight. Omega will likely get the same treatment.