Hi, welcome to Superpower Wiki! Thanks for your edit to the Primordial Embodiment of Darkness page!
She had the power before so she counts as a user, plus some of the other users were still defeated permanently and they had the power and they are considered users.
And she can't die even if she exerts herself, since she tried that and all that happened was the disaster that led to the creation of the red hole.
I read the entire series. So I know for a fact that isn't what happened.
She can't die unless ganta kills her. her regeneration won't let her. And believe me she tried.
The wiki even says the same thing.
Sorry I was busy with something else.