Aspiring Writers Group...a creative writing group discussion

This is more of a character idea than a story idea- I’ve got a very rough idea of the story, but I want to focus more on the villain to help me develop the story first. Really the only thing I’ve got so far is a few lines, like how he became villain. Honestly this is the only stuff I’ve got so far, I’d really appreciate some help on actual ideas! The setting so far is that these two girls are trying to invade the villain’s mind, and they have succeeded, but the villain has taken over Ena’s mind and is speaking through her body. I don’t know yet if Ena and Ana are twins or if their names are just coincidences.

“They said it was impossible. That giving up my essence would kill me. How wrong they were,” Ena spoke, in a voice much different than her own. It was clear she was in a place far from Ana now.
“From the beginning, they said I was a madman. They said I was crazy, insane, delirious.
They told me I was fooling myself.”

Each sentence was punctuated by Ena’s twitching fingers, struggling in vain to regain control of her body.
“I knew from the start they’d be wrong; I was right, and they didn’t believe me. But that’s when I realised,” she spat, turning to face Ana, “that
I
Didn’t
Care.”

With a whoosh of her cloak and a sudden whirl of her finger, Ena slammed to the ground, her eyes completely black and unseeing.

It looks really cool!

Yes it is fantasy, I’m still working on all the magic stuff to make it fantasy, but that is the end goal. Thank you!

I think this would be strongest if used as a prologue.