I mean there should be more psychological consequences to being locked in a room and having your leg chained. Even with a cat there with whom he can interact with he said it himself that he was bored so I conclude that there isn't enough cognitive activity to keep him perfectly sane. I mean he should at least consider that his younger brother is mentally ill, but he seemed oddly ok with it all, even caring towards his brother. Stockholm syndrome is probably the best conclusion, but I highly doubt that they would think of that for a story so simple yet flawed.
Even so I'm a sadist and I highly enjoyed it.
Is it just me but every single expression on Kang Jinha's face looks like he is about 5 seconds from breaking down in tears. Except for when he's kind of happy, then that smile just lights up the whole world, and of course right after that the world just shits on him.
I'm not saying he's perfect, cuz frankly he's a huge douche, but it is reasonable.
He's the cutest lion monster ever!!!