Bewitched with a Bite... or not?

Everything started to become out of ordinary when her grandma met her granddad and conceived her mother. Fights between clans started. Everything changed when her mum fell in love with her dad. The difference is not negligible, it is big that my grandparents even wanted to separate them. Everything escalated when he barged into her room. That night that was supposed to be an ordinary party turned into a massacre.