THEBRAINTRANSPLANT
IS NOT A FILLERagain, pls know what filler means.

okay I'll explain the reason and everything that is connected to the brain transplant (based on my understanding)

why did they perform a transplant?
- Bareum has a low chance of survival even after those surgeries bcos his brain was severely damaged. So in order for him to survive, they needed to do a transplant.

Why did he just remembered those killing when he has part of yohan's brain?
- first, the part of yohan's brain that was transferred to him is not responsible for the memories. Those are his memories to begin with, and he had an amnesia right? +++

So if there are events related or the same as the events on his memories, it'll trigger his brain which causes him to remember his killings. Hope u get my point here

He thought that those were yohan's memories, even the politician, the doctor, everyone. Why? The whole country knows that yohan is the serial killer (even if it's not true) so ofc he'll think that way especially when he has a part of yohan's brain

Because of that, daniel lee made him as his subject. So the dark hero thing started. And because of that dark hero mindset, he let out those frustrations, confusion and uncontrollable killing to those bad people.

The brain transplant is the reason why he has real emotions now. The scriptwriter wanted to see psychopaths feel the pain. This is the main reason. And we saw how he started feeling the pain and guilt.

NOW, THOSE THINGS HAPPENED BECAUSE OF THE BRAIN TRANSPLANT. IT IS NOT A FILLER. AS I SAID, MAKE SURE YOU UNDERSTAND EVERYTHING FIRST BEFORE SAYING THAT THOSE EVENTS ARE FILLERS. HOPE THIS THREAD HELPS YOU UNDERSTAND WHY THE BRAIN TRANSPLANT IS NECESSARY.