>>93469490That's not entirely true.
Malekith would've still attempted to plunge the universe into darkness because that's the natural environment of the Dark Elves, but would've been defeated by Odin's father, Bor.
However, Bor would murder Malekith's wife and infant children in front of him after he had surrendered, as punishment for his actions, and that's what would've fueled Malekith's centuries-old vendetta against Asgard.