Well, no one in the cast can get pregnant, so that's out the door.
And what is nts?
Nts is netorase. It's mostly used in a negative connotation implied cuckoldry but still somehow with the full consent of everyone, so not ntr (netorare).
I assume it's already implied, but in a positive and mutual sense as I saw in the demo's "exclusivity options" between 2 characters and the MC, but i was just curious if there would be a sort of humiliation path or dommy character that Isaac could choose to surrender control of the whole harem or even a few characters over to enthrall over him? Again, only curious.
This game is phenomenal. I'm super invested and enamored by the motives, characters, and personalities of everyone I've encountered and yet to encounter. Best of luck to your project!