Born into a rich family belonging to the House Magus of Oishi, Cosmo spent a lot of time learning magic at the school there. Not too long ago, they've begun to travel around the continent, looking for new things to learn on the front of magic. They are currently staying in Dawngate, where the local problem of corrupted wildlife and other mysterious happenings have piqued their interest.

They tend to use their (family's) status and money to get what they want, even (or perhaps: especially) in situations where they probably shouldn't be getting what they want.