What do we actually know about Jinsung? He is extremely high ranked member of FUG and he used to be an important member of Ha family.
But, is he Ha Yurin's grandson, or maybe even one of her 2 sons? We know that he is as strong as a slayer, but how do we know that he isn't a slayer himself? I would say that is rather probable, given his strength and influence. Hell, he was chosen to take care of Baam, probably the most important member of FUG. He also used to train another slayer, Karaka. We also know that he is a leader of "pro-Baam" faction in FUG.
I hope that we will get to know more about him, as a meeting between him and Yuri may happen in near future. What do you think about him?