>>96492529
>No character will ever truly die
Wrong, characters die or are retired in 40k sometimes. Like pic related. Or Creed.
And since late 7th ed there have been plenty of conquential events for many factions in the lore. But Nids are not just one of them.

They're just interesting nom-nom bugs, which is great but doesn't mean they're more than baddies of a edition.