Bethany

Once Bethany was an Astral Fairy with a yellow aura, essentially in charge of helping keep the Archives in order.

When the Citadel fell she found herself lost along with the others, and then she came into contact with Howie Radagon. Interested in the secrets of flesh warping, Bethany set herself up with the wizard (and later his wife as well once she was revived) to be the keeper of Rook's inner pocket dimension.

The creature had grown so large that its interior was just its own space, and to help unlock the secrets it might hold she agreed to live in the warped flesh space of its innards. There she has remained ever since, warping her own body into something more than what she used to be as a way to acclimate to her new environment and experiment on herself in the process.

(This creature was created by one of my players, Dwagon!)