@PeterH and @echo_jk thank you very much to both of you for the ideas and feedback. It was very helpful
No art for this update, I'm just going to share some thoughts. So sorry in advance, it's going to be a long read.
I did a bit of thinking and research and I think I may have found some ideas that will allow me to keep the same character. I found my inspiration while reading about aztec mythology. There were some deities that I think could fit with what I already have.
First, the god of death Mictlantecuhtli: A skinless skeleton with a huge open mouth used to swallow dying stars and men. Wears jewelry made of humain remains, such as a necklace made out of human eyes.
Then Cipactli: a sea creature part crocodilian, part fish and part toad. Is always hungry and every one of its joints is adorned with a mouth.
So this gives me a few potential design elements and I thought that my character's power could be something like lifeforce/soul absorbtion. Maybe she could have a passive ability that make things directly around her decay, but then she could open her mouth (or multiple mouths) to actively absorb the life out of people on a much larger scale.
I still need to think about it a little, but I think it's the beginning of something!