
He's overpowered yes. He lost his fear towards the monsters and instead started thinking a bit more logically because he slowly lost his humanity. Really the only thing keeping him "human" is his loved ones and his sense of responsibility. He opted out the S rank Japan and Korea team raid to spend more time with his newly awakened mother, even thought about the Giants Raid in Japan more than usual simply because his sister said he shouldn't go. He lost his fear towards the monsters, and instead fears for what may happen to his loved ones if he stopped what he was doing. He even has cute shadow monsters who have their own personalities and he even treats them well, such ADORABLE interactions really. He is a good mc, we grew with him, watched him start thinking rationally, watched him break that for the sake of his friends and family, cheered for him for every battle and gripped our phones when the story circled back to where it began.
He is overpowered but rightfully so. The author is dragging it out a bit but I love every moment of it. It's not a story for everyone, but it's worth the read til the end.
Also, points for him for not having a love interest.

FL just pissed me off from the first chapter onwards. I don't question why he broke up with her, I really hope she has a good character development because rn she's shit.

https://mysticalmerries.com/series/new-years-taste/ for more chapters, FL already reflected on her flaws

I hope they would at least show all the harshness and the evil done to them so we can see the build up of her anguish and his resolve and how they found solace in each other. It would've been nice if they show how the fl's psyche burned and broke, and how the ml strengthened his resolve. I really hope they did this first so it would make more of an impact to make us care.. but I'm sure it'll be there somewhere..

He's crazy.. like insane almost joker like, also.. I can't say I feel bad for the those girls since technically they deserved everything he's dishing out. I understand his point of view and how damaged he already is. He's literally insane now with only one thing in his mind that'll give him peace.
This manga isn't for the light of heart or people who get triggered easily, it's not easy to stomach albeit interesting. They're all at fault, the kingdom's higher ups and him but the difference is keyaru has a justifiable reason why he's doing this while they didn't.
If you heard of this manga and have been warned about the contents and don't think you can handle it, don't read it at all. Seriously stay away, it's a bloody revenge prn. If you have a problem with this after you've been thoroughly warned then please address your problems to the artist or the writer or the company instead of shouting at people in the comment boards who expressed their opinions, everyone has different opinions of you didn't realize it. It's all in the summary and the genre list itself, so if you don't like those already then don't read it.
I've read much worse than this, some I couldn't stomach, some downright made me vomit and paranoid but this didn't. It just made me think of how much pain someone had to go through to snap this bad. I'm not saying his actions are right, I'm just saying that I see where he's coming from.
This isn't worth the read until it's done. It's too vague and the characters are just annoying. It started awesome then dipped almost immediately. Its not worth the stress to read this until it's completed.