Ok so the main character trying to get revenge for his parents? (Kinda vague on this it was a while ago that I read this) he trains to get stronger and gets a job in a morgue so he can kill people. On the last day of school he decides he no longer has to hide his strength and beats up the dudes who were bullying him. He later meets an old dude who decides to train him properly for killing and shit, I can’t remember what it’s called but I’ve been looking for it for ages. ┗( T﹏T )┛if you know it please tell me
Not really what was described but this has a lot of similarities https://www.mangago.me/read-manga/juujika_no_rokunin/
I read this a while back, it was about a guy who wanted to get revenge on some people and so he did a lot of training so that he could kill them as well as working at a morgue to get used to dead bodies. He kept his strength a secret at school until he graduated and then beat up these bullies. That’s all I can remember
Always happy to see more chi! (☆▽☆)