In X, Anima is summoned via the fayth made from Seymour's mother. This is the only instance of the summon in the franchise.

The term "anima" has nothing to do with breath. It's most widely known use aside from a fantasy buzzword is as a representation of a male's inner femininity. (Animus is the inverse.) The other key one is being another word for the soul in Christian theology.

Now, I'm not saying it's not Anima. We... don't really have anything to say one way or another, though, and for a "traditionally" female summon to be male would be kind of out of left field in a game that prides itself on honoring franchise history. It would be far less pedestrian than Ilberd turning out to be the Griffin, at any rate. Were I betting man (and I assure you, I am not) I'd still go with some bastardization of Rhalgr - barring that, Shinryu, given the circumstances surrounding the summoning and what we know is going to be called on to combat it.

Anything's possible though!

... we are likely going to end up fighting it, though. Even if Omega does blast it with the Wave Cannon, if this thing really is more powerful than freakin' Bahamut that alone will probably be insufficient. Severely debilitate, yes, but not finish it off - even weakened, we'll still have a rough battle on our hands, and having a final threshold guardian and finally getting vengeance on Ilberd before going on to liberate Ala Mhigo are both practical necessities.