Does MC have sex with all of them? Why does he have sex with them all unless it’s non co...

He has sex with all of them, and it's non-con and dub-con. It's also a harem endgame with all of them, so far.

I hope it is harem endgame. I am tired of one ML endgame, if you know any even Novels, please let me know of harem endgame stories where they aren’t really jealous of sharing mc. I’m a big novel reader too.

And so it’s all non con/dub con with them? He never once initiated it or idk, just enjoyed it?

He sort of enjoyed it at times, and initiated it. But, (I'll try to be vague, as to not spoil) he has a certain body condition that makes it that he has to have sex with them, which is why i say it's dub-con because I'm not so sure he would enjoy and initiate it all if he didn't have that condition. That's why there's this feeling that the MC didn't really get to choose, and be completely consensual.

I don’t mind spoilers. I love spoilers, feel free to share. And what body condition? Hyper-sexuality (well more physiological than physical I guess)? Or something else, fantasy?

No, they're all "lab rats". The doctor wanted to make superhumans so he made the MLs, but they instead became like "animals", and uncontrollable, so he had to reel them in and control them by making a "mate" which is the MC. The MC would go into heat, and they would sleep with him and since animals are loyal to their mate, they wouldn't disobey the doctor. But, the MLs ran away from the doctor, and the doctor set the MC free, but erased his memories, and the MLs had no idea that he existed since they never met him in the lab. So, when they meet, poor MC would go into heat, and they would sleep together, and the MLs would get obsessed. And, since none of them can let him go, and the MC can't survive without them either (the heat won't stop until he sleeps with them), the MLs set up a schedule, and work together, but would like to get rid of the others if they could.