Essentially what is going on is that Rupert's mother is descended from an ancient clan of people who can be manipulated like a puppet or a slave. She was a dancer back in her country Wileton and sought after by many people because she was talented and beautiful. She loves a prince named Claude who loved her enough to buy her a title so they could get married. Unfortunately the nobility in Wileton realized that they could use her beauty In order to seduce the emperor of this country (the one they are currently in). She has to obey because she's being controlled like a doll. The current emperor is an abusive pr*** -- to the point of where he actually kills her by throwing her body around like a doll. However because he refuses to live without her, he has Rupert use his alchemy to revive his mother so he can have s** with what is essentially a corpse. Rupert does so because he (and his mother) wants to be emperor and the only way to do so is to obey the emperor's will. The mother wanted him to be emperor because Rupert is not the emperor's biological child and she thinks the greatest revenge she can have on the emperor who tormented her, raped her, and physically abused her to the point of death is him knowing that the future emperor is not if his blood. This seems to be moot point however, because the emperor knows that he's infertile and that none of the kids are his, therefore doesn't care who the throne goes to.
