>>96491425
If Necrons wanted to they could end humanity with one push of a button. They don't want to because they still need them for experiments. Chaos is also no problem for them as are Tyranids or Orks.

>>95894459
>but just some superfluous other dimension that we could seal off
Necrons literally have the tech to do just that. Like could just fix the chaos issue overnight if they could be arsed.