Elsie
A mysterious former student of the academy that somehow got turned into a fairy(?). She's a self-proclaimed beauty and a massive closet pervert, likely close to 100 years old. Despite all this, she's totally inexperienced. She needs energy to keep her human form. If she runs out, she will turn into a ghostly presence with almost no link to the material world. The only way for her to regain energy seems to be by collecting used panties, the fresher the better. Her body seems to be immortal and doesn't age. It regenerates quickly back to its original state (hymen included). She probably can't get pregnant either, but she never tried. Her memory of the past is hazy, but she doesn't care and instead lives in the present. From the looks of it, she died a long time ago and for some reason didn't move on to the afterlife. She might have some kind of regret that holds her back (or she just likes panties way too much).