if you mean towords Baam and the others then no he's not.
Well to be a traitor he has to be loyal to somebody or something, and I have some recollection that the first time Hwa Ryun called him "prince of the red light district", she suspected him to serve his own interests. Beside, he's doing what he has to do in order for Cassano to heal Horyang, so no.
This man is wise. Give this man bananas. But Wang and Baam might end up separated for long now. SIU had planned Rachel and Wangnan's relationship for long, what implies that it might last in time, thus making him some kind of TR8TR !
Oh, and him trying to kill Rachel, yeah, that's what he said. But Rachel's plot armour is way to thick.