
It's gonna be long, but I'll try to keep it as short as possible • ‿ ,•
His father went missing and was assumed dead... 10 years ago.
In chapter 56 a mysterious guy appears and in ch 57 they try to interrogate him. Apparently he was stuck in a dungeon all this time and when he got out he was in the United States, although he went missing in South Korea. It's already weird that he is on the other side of the globe, but what's even weirder is that the gate he was stuck in was an A rank and he easily defeated a bunch of American hunters of the same rank. They believed him to be a monster.
A guy who hated Sung Jin Woo was the one who interrogated the father and upon learning his identity he claimed that he really was a monster who was to attack them. Then told the father that Sung Jin Woo was dead and so he really attacked him and so the guy ended up in a hospital. He still claimed the father was a monster. The father ran away and we haven't heard of him since then.
Sung Jin Woo didn't know that his father was possibly alive and now they tell him that he's not dead and also a terrorist/monster, and that's why he's furious.
I didnt understand well Im confused T﹏T