User blog comment:B214/Talk About What You Want! 3/@comment-24098614-20150429020209/@comment-3965848-20150429134829

they have 5 yr contract but I think they can extend thier time.

Also, I think Yubelluna was a Magician before becoming a Devil, because she seems to have more magical ability than anyone in Riser's Peerage, flies without wings, there's also the way she dresses, she even carries a staff.