I'm still confused about what is going on here, the visuals are amazing looking. I guess if I am assuming right she is digesting souls.

The confusion is intentional! But yes, you're on the right line of thoughts.

Ah cool that clears up the confusion enough for me. I look forward to seeing more then and to learn what is really going on.

So I'm confused.

Is her soul in the process of evolving into a Eldritch Abomination?
Is her spirit already partially devoured by one?

Yes.

Uh, a mathematical answer doesn't really work here.

Yes it does. Both those things are true. That's pretty much how magic works in a setting like this.

I was asking if her spirit was turning INTO a monster, or if her spirit was being EATEN by a monster, there's a fundamental difference there.

No, you just don't understand: those two things can both happen at the same time. The eldritch being takes bites out of her and simultaneously the process transforms her. Although the original word you used is better: digests.

You are attempting to assert that the processes must be different things and cannot be reconciled. I am telling you that is an incorrect way of thinking. The processes are happening simultaneously. They are also simultaneously causing each other. Using the digestive metaphor: because the thing she gave herself to can digest spirits, she is able to digest spirits. Doing this makes her an extension of the monstrous thing, taking on monstrous qualities herself.

Great, now her soul has cancer...

I like the whole 'she is the mass, and the mass is her' this image brings to mind; really makes me want to see her gain some kind of spiritual powers from all of this :D

Maybe, having seen what happens to souls when they die, she's chosen to become a true after life for the dead rather than just trying to become a bigger fish herself, becoming a collective consciousness for their souls, rather than them just being fast food, realizing that binding your soul to the world of the living is a short term solution in the face of eternity, and making herself a bigger fish won't solve the real problem.

What if she didn't EAT those two ghosts, but simply their souls and hers became one, their experiences and emotions not being lost or used as raw material, but instead being added to a whole. Becoming a true loving goddess for souls to become one with when they die, rather than food for an unloving goddess.