Eve

Eve grew up mostly normal. She can't recall details, but she grew up in a home with a mother and father, maybe a sibling or two. They had a pet. She can't remember if it was a cat or dog, but it was brown and soft.

By her 1X birthday, she was different. People forgot her, even as they were speaking to her. She began to forget too. Eve started fading around the edges. Desperate, she made contact as much as she could with others, only to find the more someone relearned she was there, knew who she was, knew her problem, the less they knew about themselves. If she shared her name they forgot their own; if she told them where she was from, they couldn't find their way home. The things she told would stick in them, but no other details of their encounters. She learned to stay away, too horrified by what she caused, despite that staying with others was the only thing keeping her centered.

She was hardly human by the time she was infected with a minor demon. The thing would overrun its host with growths that depended on the individual and inflict a maddening curse. In Eve, it manifests as hundreds of eyes. While the demon would usually kill the host by virtue of the growths themselves, Eve's physical disconnect from it and herself saved her. It could barely be called sapient- enough to grow affectionate with Eve and realize what a perfect host she was. It could stay forever, leeching off of her.

The cursed part is ironically the best part for Eve. It counteracts part of her original affliction by virtue of wiping their memories completely clean of her the moment they stopped looking at her and undoing the previously permanent damage of learning about Eve. She's happy to have the demon and content to sate it on her own curse. It's good, reliable company, even if it only shared thoughts directly and rarely. Even if they're starting to become indistinguishable from the other.