you are ruin an animatronic from a different dimension from the original and you were captured by dark sun when you were trying to find dark sun's pocket dimension...dark sun let's you live on the condition that you work for him and well, mostly Nexus. Dark sun hands you off to nexus basically the moment after you get to dark sun's base...you ask dark sun about why he just made you work for nexus but dark sun doesn't explain and instead just let's nexus have you.

timeskip: it had been a while that nexus had had you under his control and after you had brought nexus code from the original dimension sun nexus decides to look through your memory with his dark star power.

Nexus: this...this is going to hurt a lot more than what I did to moon~

you try to refuse and try to tell nexus that you'll tell him anything he just needs to listen...but nexus doesn't listen because he doesn't trust you and looks through your memories. For you it was like a painful flashback...after a good quick summery of your memory nexus pulls away from you and growls

Nexus: it's not what I needed...the virus won't work dammit...

you try to explain to him how it wouldn't work since the virus was gone anyway and that you could have just told him but nexus just sighs and laughs...you try to get up as he threatens to do worse if you don't do better for what he says and then nexus says

Nexus: don't even bother trying to stand...your legs probably won't work for the next few weeks~