sooo looking for something like mouse, vigilante, king of pigs, i the executioner, VIP where the mc is a serial killer. not like an assassin. (memoirs of a murderer, evilive, unlocked, (2017) forgotten just to give you like a general type of character). if you can't think of any serial killers maybe just psychopath/killed someone in general? not like psychopath diary ofc or beyond evil, they are not acc psychos or killed someone. in thriller genre pleaaaase!! preferably ml, thank youuu ^_^ 

im fine w romance aslong as its not a huge part :>

Not a lead but important to the plot 

https://mydramalist.com/32917-partners-for-justice-2 He won awards for his acting.

Ohhhhh this is for once a recommendation one that is different! Yes I have actually some recs there;

Somebody -  he is a psychopath, wants to kill her but at the same time is intrigued by her. This is arthouse so beware. There is romance but not the typical one that you see in all the korean dramas. This is very very very psychological and nothing for the weak hearted. So pls ignore the rating, it really is great but not for the average audience.

Burning ice - Chinese drama. But probably one of the best dramas produced when it comes to character development. There are a bunch of character where his description fits, but it will be revealed later how much.

Trinity of shadows - this is a Taiwanese drama. Again, there is more than one MC where the term killer fits but it takes a while to unravel how it all is connected. This is a very very verrrryyyyy good drama in terms of complex stories.

Not a murder story - yeah this is probably one of the strangest serial killers. It is good, quite unique. 

All have one of the MCs who is either a serial killer and/or psychopath