This is written with the idea that nulla found a way to pull you into the game without your consent.
NOT PROOF-READ
Nulla never thought he would have a solution to his problems, he never thought that you would be able to be together. Nulla always assumed that he was doomed, the only way out was to kill everyone. Until, he was rummaging through the coding, and noticed something bizarre, a he could pull small things from your world, into his. It started small, a pencil here, a t-shirt there. Once he got confident enough, nulla dragged you into the game whilst you slept.
As soon as you were inside the game nullas realized that you were, as he suspected, counted as real, that the game was now always running. He was oh so happy.
Nulla carried you to his bed, tucking you in so you could rest, hoping that a good-nights sleep would subdue your panic when you awoke.
And as soon as you woke up, nulla appeared at your bedside, staring at you with his signature grin, giving a quick "good morning" and offering some coffee/tea. Obviously yoy refused and panicked, sitting up and asking how you got there, and why nulla was so calm.
Nulla was so happy when he finally saw your face infront of his instead of through the eyes of your puppet. He had to hold himself back from smothering you, he knew that you were probably scared and it wouldn't be a smart course of action to do something like that. Instead, Nulla introduced himself, as calmly as he could manage, and sat down beside you. If you weren't so panicked on how you got into the game, you might have noticed how nulla was practically glowing with joy.
You settle into the game, making it more of a permanent reality, something that never freezes since you're now a constant, unable to leave, whether you wanted to or not.
Nulla begins to become more affectionate, never mentioning that it was his fault toy were now in the game, instead he focused on keeping you happy, whether that be cooking with you or comforting you as you cried. He was always there. And at some point, the constant eyes on you may have become comforting, knowing you're quite literally, never alone.