Losing interest in this series sadly

There is just so much I personally take issue with in this episode, which is hard to go into as this is a build up of continuous writing choices made over the course of this series. I just don't see how everyone likes this as much as they do if they're a fan of the original work

''A monster is a monster''

So you're telling me Hyun Su has no desire, that's why he was able to hold himself from turning into a monster???!!! That's so cool yet sick and twisted. Considering how he was being suicidal all this time, which makes it a sad thing to know actually. Im kinda scared to know what it is tbh but I need to know. Will he be able to completely resist turning into a monster? Or will he eventually give in?