Main character is not so good guy/girl and doesn't change much for better

Vincenzo - this one is also a comedy (so be prepared) but the main character is dark and stays that way throughout the drama. The way he deals with his enemies is brutal. The quote with which he ends the drama is: "Two days ago, I used three Luciano family members as manure for the vineyard and took over the olive plantations in Malta. I'm still a villain and couldn't care less about justice. Justice is weak and empty. One cannot win against any villains with justice alone. If merciless justice exists, I am willing to yield to it. Even villains long to live in a peaceful world. However, since that's impossible, I've taken up a new hobby. Getting rid of garbage. If I don't do that, people will die buried underneath the garbage. There's one last thing I'd like to say from a villain's perspective. Evil is prevalent and vehement."

Kill It - ML is a professional killer. I personally enjoyed this one a lot, but it's been a while since I watched it so I don't remember many details. Spoiler about the ending - it's sad

Bloody Heart - this one is historical. The ML is a king who's pretty grey-ish but has a lover who keeps him in check. It's mostly about court politics so I'm not sure if it's your cup of tea.

 Marpleme:

Please reccomend me a drama  where ML or FL is NOT a good guy/girl and stays that way  ( or at least doesn't change dramatically - may change a bit but still remain in rather grey-ish area).  She/he doesn't have to be evil  but I wish to see a very flawed characters, ones  who don't get rid of most of their flaws when they fall in love with a good one. Give me all kinds of unrepentant liars, manipulators, cynics,  self-centered and anti-heroic characters! Bonus if it's historical. No Thai BL's  please. 

 In this post I'm not looking for a reverse hero journey ( from good to bad) though but  astory where main character stays consistantly antiheroic.

 So far dramas I watched that were close to this are: Word of Honor, Win the Future - loved/liked both. 

At the end of the drama, the ML is still deeply flawed (in some cases the ML might try to be good or tone down his flaws for a while, but it doesn't last):

• The King's Woman
• Empress Ki
• The Smile Has Left Your Eyes 

The ML generally remains deeply flawed (with some instances of decency) until the end of the last episode where, after a separation from the FL, it is implied that the ML improved or the audience is told (but not shown) that he improved:

• Moon Lovers: Scarlet Heart Ryeo - The FL dies in ancient times and her soul returns to modern times, where she learns that the ML's role in history has changed from a tyrant to a good king.
• Cheese in the Trap - The ML leaves the FL to work on his serious issues. In the last moments of the drama, it looks like the ML has opened one of the FL's emails for the first time in years, implying that perhaps he has gotten to a place where he thinks he is better and ready to revisit having a relationship with the FL.

Misty is in a category of its own. The ML and FL are both flawed. The ML and FL don't change that much over the course of the drama (the ML makes a few decisions near the beginning of the drama that make him a terrible person, and then he just solidifies that over the rest of the drama, while the FL gets a little better over time) but the narrative reveals that the FL is a better person than she originally seemed and the ML is a much worse person than he originally seemed.