It's been a while since I last read the first series, so I'm not sure what I've misremembered and what I may have forgotten, or if I was way off base.

At the end of WoBM, I thought I knew what he was. A sword elemental.
I'm not entirely sure why, that kind. Probably because of the annihilation aura.

Since then, I haven't seen any comments that agreed or seemed predicated on the same premise.

And I can't recall what it was, or why, but at some point I became convinced that was completely wrong.

Now I'm completely confused.

Summoned creatures that think they know what he is are afraid of him.

A certain elemental considered Keras to be a kind of relative.

He's not human, or not entirely human.

Is he an elemental?
Is he half elemental?
Is he an extraplanar being, like from another dominion (which may be like or the same thing as an elemental)?
Is he the son of a god, like a world maker?
Or the son of a "god," like the Teos pantheon? (Sorry, forgot where the apostrophe belongs.)
Or is he a fragment of the world maker who died? The one who's death makes the Dominion Breaker unusable for its greatest purpose.

If you know, just tell me and save me the time if rereading the whole thing.
Or if there wasn't a proper answer, but you're sure you know, go ahead, hit me.

Spoil me, please.