
Yup yup! Pilgyeon didn't know his real name and just called him with his alias, "uncle" or something. But he is also the guy that Pilgyeon "killed" because he wanted to end Nanmu's life... If I understand correctly, WGT is either the son of the person who took Nanmu and his friends in a pseudo orphanage where they grew up miserably before Pilgyeon's father adopted them... That's why Nanmu and WGT had a lot of history together, even got involved with the same woman too.

WGT is truly a psycho, considering that he trained a child to be cold and emotionless. He hurt Pilgyun whenever he cry and forced him to smile instead... He kidnapped Pilgyun simply because he disobeyed him, almost killed him and protected Nanmu from their fuck up organization (swamp).
It is also safe to assume that Pilgyun became Nanmu's weakness most especially in the future chapters.

The scary part is that, the author hinted the readers that one of their two on-going story will have a sad ending...
Either smyrna and capri or miscreants and Mayhem might have a tragic ending and I don't wish that Nanmu and Pilgyeon will have the bad ending for their love story...
The child already experienced a lot of pain, so he should have the happiness with Nanmu that he deserved.
Gosh! I'm getting so mad!
After knowing what happened to chapter 66, I wanna bury you alive, Wang Gong Tae!
I won't let you live longer, as you are a big threat to Pilgyeon and Nanmu's happiness...