It’s just it wasn’t written on their page!

Comic lore covers all of this but it hasn't been totally explained in the MCU yet, but with no it's like the eternals out we are getting closer to the begining of time

Pretty sure that was just an ancient legend.

they came from nowhere

You mean, they born from nowhere, @Hornedrimglasses!!

@Hornedrimglasses And where did nowhere come from? I can do this all day!

Eternity

And where did Eternity come from?

Eternity is outside the laws of reality, kind of like the way religions talk about God. Not to get to philosophical, but the basic idea is Eternity is an essence beyond everything that doesn't need an origin, it (or she) always was

@Zecharya Greiniman there's always, ALWAYS, an origin at ALL, NO EXCEPTION!