you can read about the general jist in her info. but basically an ancestor made a deal with a demon for generations to come, meaning that any direct descendants would be blessed with the power, yet they would still be indebted/bonded to him. he hasn't come to call on the family in at least a century, maybe more, so it's been assumed that he's either dead or just uninterested in them anymore. there's a lot of more things that can be brainstormed upon!