Overpowered and merciless or just overpowered?
Merciless
The famous Solo Leveling has an MC that isn't afraid to kill, even if he's not as merciless as this one. Return of the Flowery Mountain Sect too. The World After The Fall has a pretty straightforward and merciless MC but not as overpowered as this one. Leveling with the Gods is similar to this but the MC isn't as power hungry. Dungeon Odyss also has MC that's isn't afraid to kill and learn but isn't as overpowered.
I Am The Sorcerer King has a pretty OP sorcerer MC but I think it's discontinued unfortunately, though if you still wanna read it, there's not much to lose because similar to this, there are a few conflict and u can just stop reading before the last conflict starts lmao. Regina Lena has a strong OP FMC that isn't afraid to kill, but it has romance and action isn't the main plot.
There's also manga about detective who kills the crime suspect called Brutal: Satsujin Kansatsukan no Kokuhaku. Joou Heika no Isekai Senryaku is also manga with merciless FMC. The Hero Who Seeks Revenge Shall Exterminate With Darkness has a very brutally merciless and overpowered MC, the entire plot it literally just revenge and gore (with some nudity and porn).
Nano Machine (●'◡'●)ﾉ
Does anyone have recommendations with a mc like this one? Can someone please drop some recommendations