So the male lead, Ryang-Ha, starts off as kind of an enemy to the female lead, Chateau. Despite this, they start working together kind of secretly. Their relationship develops and they become stronger allies.
Although romance isn't the main focus, they get many cute moments together, but it isn't "lovey-dovey", just Ryang-Ha being cute and Chateau being like ',:| Still cute though *-*
In addition, there is plenty of action, blood, and some mystery as well. And of course, the characters' backstories are revealed later. Those were the greatest chapters, in my opinion. Interesting stuff.
And despite there being action and blood, Koroshi Ai provides you some comedic moments as well.
However, the fact that Chateau frequently needs saving bothers me a bit. She does get her cool moments though.
In conclusion, I really enjoyed this manga and am looking forward to future updates. You should definitely try and read this manga if you get the chance.