Dubcon like CRAZY throughout.

Non-consensual somnophilia - ML touches + grinds himself against MC while he's asleep multiple times, both on and off camera (a few scenes are written in detail, but it's mentioned that he does it most nights). Never discussed or revealed in the main story.

Oodles of manipulation - ML shows a very different face to the MC vs everyone else. MC is very much unaware that the puppy he's raising isn't as naive or innocent as he seems and there's soooo many layers to this.

Quasi-drugging/addiction - There's an omegaverse aspect carried over from the MC's first life. ML starts to present as an Alpha and learns that his pheromones can affect MC's mood and sleep. He basically doses MC every night with pheromones so he goes into a very deep sleep to commit the aforementioned somnophilia. He also realizes that because of his nightly actions, MC can no longer sleep without him which bleeds into...

Forced reliance/emotional manipulation - MC and ML get kidnapped and are separated and imprisoned separately. MC suffers due to the isolation and bare bones quarters and starts to heavily rely on the ML's allowed guiding visits to keep his sanity. He also can't sleep without ML and starts to deteriorate mentally and physically.

ML is aware of this and admits that he is capable of getting them out pretty much whenever but decides to stay so he can use MC's vulnerability to make him rely on him and see him as more than just a child. ML pretends that he's suffering to tug on his heartstrings and to allow the ML to push past the boundary of intimacy that the MC has already set. He waits until MC is at his breaking point before breaking out of the villain's hideout.

Voyeurism/slight exhibitionism but not for gratification but bc ML doesn't care - In this kidnapping arc, the MC's prison is equipped with cameras and they are being constantly watched. ML pushes the intimacy x10000 in this arc and MC is often too caught up with pheromones to be able to resist or hide. ML also jerks off a ton post-guide visits and doesn't care if his minders watch.

The reason why the villainous character never gets sacked from their workplace despite the numerous complaints the leading man of the book filed was because OG!Lee Taerim is simply a better employee compared to the book's protagonist, who mostly rolls around with the book ML.

a relative abundance of S-Class Espers

he managed to acquire some alpha traits. Add the part where he was abducted as a boy and got experimented on until he was barely an adult, treated more like an object than human. He goes on a rampage when he awakens and the person who saves him is our MC. MC then takes care of him until he can somewhat function in society. MC, thus, is his major life benefactor.

the part where they get kidnapped and ML puts off escaping partly because he wants MC to increasingly want him, risking MC's well-being. And even before that, ML devises ways to make MC also dependent on him. Like, extensively using his pheromones to lull MC to a deep and relaxing sleep, which makes MC unconsciously long for ML's pheromones to get restful sleep.

Uhh... MC got kidnapped and ML took the chance to make MC dependant on him. Afterwards, he destroyed it like no big deal. Hello? I thought the evil organization is a big deal but apparently ML is just too over powered 🥲

Well... Again, MC got kidnapped and ML took the chance to make MC dependant on him. Afterwards, it leans very heavily on the omegaverse side with pheromone attraction and dependancy.

They have practically 0 dialogue after OG MC runs away and their story is kinda told in the background. Granted, I haven't read the side story. Might update it if there's a proper conclusion to this part.