Yeah I think the biggest problem is that he abandonned his home country when they really needed him.
Cause he was their number 1 and ,at the time, the only person making any real progress in the tower.
So after he left and before Bong gave the other player the Sword, i would geuss that the fear of the tower collapsing was really high.
And I think the fact it was Japan kinda made it worse because of the tension the countries either have or used to have(especially suring WW2)
He is a bad person, he exploit the benefit of being no.1 in republic of korea and hoard equipment for himself and took them with him and said the government didn't support him enough which is complete bs considering there are other people that could surpass him but they lacking in support (there's missing info that's in novel but I can tell you he's pretty bad through and through)
so true!
is it just me or is the blue haired guy who migrated to japan not that bad of a person like yeah he has a bad personality and all but he seems like he genuinely wanted to climb up the tower right? its not like he just stopped climbing because he was satisfied with where he's at