He has a LOT of red flags honestly. He's related to the king, and the fact he's alive when the king killed off the rest of his family is a massive warning sign. There's no way the king would've left anyone alive to dispute his rule or create potential heirs that could cause trouble later, so SML would've manipulated the king somehow into leaving him alive. I also think he killed MCs mother, because as we just learnt he felt MC didn't pay attention to him, but if his mother was dead, especially on the night the king was killing his entire village, SML would be the one MC would run to. He planned the entire thing to get MC for himself, but he didn't expect MC to go to the king instead.
Anybody else who's just head over heels for Raonhiljo?
(I know that he is probably the bad guy here)