Teddy

Teddy was originally an experiment by Bethany to create a sort of 'guard dog' for herself, as the innards of Rook are a dangerous place given the products of its natural asexual reproduction cycle. However, Teddy kept growing to enormous size; too big to roam the exterior world because he would attract too much attention.

So, Bethany installed Teddy as the protector of her archive instead. He has remained since, gaining intelligence as he studies in between fending off the natural creatures of the environment and content with his place.