I don’t understand why MC hates the emperor can someone explain ?

So the MC and emperor are family (brothers) it started when he killed everyone in the court in front of him and took the throne saying he's doing it for him and country. Underneath the emperor has been isolating him his entire life cuz of his obsession for him. The emperor killed his fiancee(idk if she died) locked him up almost raped him so he away. Now the emperor kidnapped him away and doing the same thing. Ooh he supposedly telling MC the dragon is dead. Now he's just insane stabbing himself just so he can get affection from the MC.

Thank you soo much