Okay, basically.

Y/N is a so-called 'normal' kid. Good grades, pretty active, talkative, friendly.
But one odd thing.
They had, weird enough, no friends.
Mainly for the reason Y/N wasn't actually normal.
At school/in public, they acted normal, sure.
But at gome was an entirely different story.
They loved staying in one room and just building things/playing video games/talking to things that weren't alive all day.
So it isn't a surprise when Y/N develops a strange relation ship with....