Spoiler

Hey it's from web novel, and it won ridibook award. Both seme and uke, in the novel are very masculine, tall, and very handsome. Uke is called handsome many times in the book.
ML is typical gwanggong, as usual, chaebol, but he is more of a gangster side personality. He has an older sister who is a doctor, and a younger brother who is stupid. He and his sister were born from the first wife, who committed suicide. His father remarried to the 2nd wife with also chaebol family background.
MC (uke) is undercover to kill ML (seme). His undercover identity is a chinese heir from also kinda triad family, and he staying at seme's house during this mission. Major spoiler ahead, the one that hired uke is actually Seme's father and his current wife. But seme is resourceful and smart, so he just play along with uke. It's never been stated whether seme is pure gay from the start or just after meeting uke. Uke was a straight before.
As usual yaoi trope, this story has rape.
ML is unusually interested in uke. Uke been accompanied by seme younger brother (son of the 2nd wife of his father). Uke was taken to many wild chaebol parties by the younger brother. Another friend's of the younger brother interested in uke, so he made a move on him, like kissing and left kiss mark, but in the end after gathering information, uke left the party. Seme saw the mark, uke said he had a headache so asked seme to bring him headache medicine. But what seme gave was something else. It made uke unable to move his body, and then seme force uke to sleep with him. Uke wasn't actually angry or anything, but more like ashamed with that incident and doesn't wanna get ridicule by his brothers if they ever folund out. But the next day, uke got drunk and slept with seme (he do realize what he was doing).
Moving on, seme actually decapitated the guy at the party who kissed uke. And bury his head in his garden where he grow vegetables. All his employees are just as crazy as him. Uke met seme's father, and uke actually told seme about his mission, because it's no longer useful to play pretend because seme already know his identity. So uke asked if seme will pay him more and uke will kis his father. I kinda forgot this part, but I think seme said yes.
Uke's brothers came to finish the mission with uke. Fyi, uke is korean but he had complicated childhood wherr in the end he got adopted and grew up in china with his two chinese brothers. The uncle who raised him already died. So the mission was to kill seme's father during ceremony of something at the company. But uke shot seme, on both thighs. Seme and his brothers then runaway to russia, I think for a year.
The decision to shot seme was actually because they found a recording, that fell in car seat, seme told his secretary after killing his father, he will kill uke. So uke felt betrayed, but uke still can't kill seme so he hurt his legs instead. During seme's injury which make him unable to walk, his father tried to replace seme at the company, business stuff, seme still won in the end.
Uke actually felt complicated whether he actually like seme or not. One of uke brother, went to korea (or china?) I forgot, seme found his brother because his brother girlfriend actually betrayed him by reporting his location to seme. Finally seme could video call uke. Uke was seen with a girl (his neighbor) both wearing swimsuit (so the look naked on video). Seme got angry by seeing that, jealous I mean. So seme show uke he got one of his brother, and seme bite one of his brother fingers off. Uke was so shocked he told seme, that that giy is his brother. For the record, seme didn't know the two guys are uke brothers. And seme really have no interest to know their name he only care of uke.
In the end seme attached uke brother finger again. Uke and his other brother go back to korea to meet seme. Seme is vulgar, so he told uke brothers that he slept with uke, but he said it like this "I m sorry for what I've done, next time, I'll ask your consent before sleeping with you", so the brothers laughed that uke went gay. I forgot which part, but there's part where seme put seme in basement, held him captive. For few days.
Ok anyways, I think the 3 of them agreed to help seme to do something. Again, the 3 of them run away after finishing the mission, they don't even take the payment money. At that time seme was high in his own delusion that after the mission he will take uke to dinner with flower bouquet. So when uke ran away the 2nd time he went crazy. The 3 hid on an island. But seme found them very fast (unlike before). This time uke was taken to another place, separated from his 2 brothers. There's sex scenes and stuff and in the end uke admit he likes seme as well. So they both Finally couple. Seme's older sister surprised but whatever make his brother happy. Seme showed uke, the eerie doll that he had, with exactly similar like uke. He told uke, next time he run away, he will make him stuffed doll, so uke can be with him forever, even in death. They go back to korea, and reunited with his brothers. Sometimes they have sex sometimes they fight with each other. They are not "cute" couple. They punch each other. One morning the brother asked if uke and seme had wild sex last night so uke told him they were fighting. And the room was a mess. But within a day all are fixed. There are many arcs in this novel. Not focus on romance. There's arc where uke killed criminal gang who kidnapped children to be sold because turned out uke was one of the kidnapped children. There's arc on the yacht party where the family of the decapitated guy seme killed was looking to kill seme & uke, I think he was killed instead. The head of this family changed. For uke and seme, on the day they were on a date. Seme removed all his bodyguards so he can spend time just 2 of them. Uke brothers of course not joining them. But seme's father take this opportunity to kidnapped both of them and tried to kill them. It's bloody arc. In the end seme's father had his head crack open because uke attacked him with axe. Uke and seme also escaped by the help of the bodyguards and the brothers. Seme's father isn't dead but in critical condition. Uke feel sorry for seme, because he attacked his father, and could make seme orphan. Seme as usual act ad if he was sad. He is super manipulative btw. When seme's father getting better, suddenly he died the next day. It was the older sister doing. She hated her father for trying to kill her brother many times. So she killed him.
The 2nd wife stop interfering as long as her son not getting killed. Seme and his sister don't hate the brother, he just annoyed if the brother does stupid things.
Seme and uke do charity together and stuff. Paparazzi took their picture together. But seme found the Paparazzi, he didn't kill him. But told the Paparazzi that uke is his lover, so next time he took pictures make them good and email the pictures to him first. Uke face then posted on news beside seme face. The Paparazzi didn't reveal uke identity. One day, a prosecutor who want to catch seme because many many cases, asked the Paparazzi who is this person beside seme in the photo, the Paparazzi just said it's his lover.
Uke and his two brothers actually tried to remove the prosecutor for seme. So they sneaked into his house. Only to found another big secret. The prosecutor was actually, his real biological brother. Uke was kidnapped very very young. In the end, they both know they are family. Seme also know this. And he tried to be nice to the real brother, but the brother keep thinking that seme is taking advantage of his innocent brother. I forgot when but uke told his brother he just as bad as seme. And the on who killed the chairman was actually him. Not seme. Then the real brother finally drop the case and stop trying to put seme in jail, because he doesn't want uke to get entangled. He never blamed uke for turning into a killer because it wasn't his fault to be raised in very harsh and violent environment.
That's it. And the rest are just side stories. Seme actually can not differentiate which brother is which because he doesn't care. And he never bother to learn their names. Seme is manipulative and very smart. And very gwanggong.