Despite not actually focusing on the romantic aspect as advertised, there still is some substantial plot that is actually interesting. Warning, it's really just about the backstories of Ryang-ha and Chateau.

Ryang-ha is a powerful, intelligent guy and he has wiped out an entire "mafia" organization. Now that's a pretty interesting story to hear about when his former colleague from said organization seeks revenge. While not that impressive, this is really the first arc of the story and shows off our powerful ML. It's a plot point, it's there, and you might enjoy it. The next arc is, surprise, more of the past, but this time it's about Chateau's life. After a puzzling incident where young Chateau is found in a car with a dead boy sitting in the driver's seat, she is adopted by a detective and his wife. Throughout the last 7 episodes, things are slowly revealed about this incident as she fights and escapes with Ryang-ha. It turns out they both knew the dead boy and how they knew him is up for you to watch.

The romance isn't there, it's really just Ryang-ha doing things for Chateau, like killing her bounties for her, because he's interested in her existence. The only real romance in this show is between Chateau's boss and his wife, of which we see a brief cute scene of them together. I really wanted to see how Ryang-ha and Chateau would fall in love but I was very disappointed.

It's just not there. In fact, what we see is a degradation in many characters over the course of the story, especially with Chateau. At first, she's seen as a competent bounty hunter who keeps her personal life and feelings very separate from work. But then she becomes weak in comparison to Ryang-ha, loses her confidence in herself, and pretty much turns into dead weight. I don't like saying this about what is supposed to be a strong, lethal woman, but it's what I saw happen. Ryang-ha just doesn't have any character development. He's a strong killing machine with an odd obsession with our FL and doesn't change.

The only character to have grown a little is Jim, despite his infuriating lack of a mouth and really odd way of speaking. He grows a pair in order to save Chateau. And that's really it. I personally hate his character so I can't speak too fondly of him.

There's just not enough depth and contrast to the characters or the scenery, and it really kills the show. I haven't read the manga, but I hear that it does a much better job of detailing the right moods and expressions. I had hoped, because of the epic opening, that it would have been a lot darker, more expressive and defined. But it's really not, there isn't that pop to the show that there should have been and it feels like not a lot of effort was put into the making of this show.

The music was good though, and the OP was a banger. It really grew on me even though I had initially liked it. There's a lot of "classical" music that gives you the feel of real espionage and professional killing, that sort of vibe. If only the art/animation used in the opening and ending was kept up in the actual anime.

It's not great, there's little to no romance, and the only real plot is the backstories of our main characters. The animation isn't true to the feelings of the story, which makes this score even lower. Koroshi Ai could have really been something if it had stuck with the initial romance instead of a connected past that brings trouble. I didn't enjoy this, and I definitely won't be watching the second season. The first season ended right in the middle of a big fight, so I just can't bring myself to justify another season that might do the same.