Nope. yagami was the princess that daikoku fell in love before. The mc uke is said to be her reincarnation, daikoku thinks that his brother is after the uke becuse of this.
Maybe you mean yasogami? Daikoku's brother?
If yes, he was the fiance of Yagami, the princess but she chose Daikoku instead of Yasogami. They didn't mention why but Daikoku hates him. Maybe he was the caused of the princess death?
Ohh yes! Thank you so much I remember it now haha sorry too lazy to read again
Wait.. Can someone tell me about yagami? Is it mentioned before that he was a threat?