I have a feeling that Seok's master was the one that got rid of Heeju by asking that red-haired hyung to kidnap him (or somethingalong those lines). I don't remember if they already mentioned this, so I apologise if I'm speaking nonsense or repeating what was already stated.
Me too, since the young master's mom death chapter that I think the young miss/Heeju kidnapping has something to do with him, that's why red haired knows him.
I have a feeling that Seok's master was the one that got rid of Heeju by asking that red-haired hyung to kidnap him (or somethingalong those lines). I don't remember if they already mentioned this, so I apologise if I'm speaking nonsense or repeating what was already stated.