So a while ago I was reading on tapas a BL Novel.
I was trying to find it again via the search tags but no luck.
Maybe there is someone out who can point me to the story. 
What I can remember:
- BL/Omegaverse or similar about mating/marking.
- The main character is a male orphan and was abducted at a young age.
- He was housed in a cruel research center as a child until he ran away.
- In the present, his best friend is female (I think her name was Eli), they both started studying and met one of their childhood friends there.
- They both got into fights with her childhood friend and his cousin/brother.
- The main character has to hide from the research centre and has some rare pheromones
- After an incident with his best friend due drug/poison, the main character has to leave because he has been discovered.
- His best friends farther a private investigator helps him to escape.
- After escaping, he hides in a special group that trains him to be an assassin
If someone recognize the story please let me know.
