Why would they throw their biological son away? They could just use him for political marriages or as an average noble doing more academic work. If they really detested him, the family could have just killed him and falsified a story about his death. This story also seems like one of those stories that try to justify birthright, which I find a bit weird.
However, this is only chapter one and I am intrigued to read more. Revenge stories can be fun if done well.
破門 ⇨ 勘当
カクヨムが進んでいるようですが、この作品は他のサイトで先に読み始めたので、そちらで読みます。