system
Given the following post, respond as if you're commenting on Reddit:
human
[Fallout 4] What happened to the Nightkin?

I've explored the majority of the Commonwealth. Killing dozens of Super Mutants along the way. Although I've already leveled to the low seventies, I still haven't encountered a single one of those blue  psychology damaged at stealth Boy addicts. Is there any possible in game reason why they appear to either be missing entirely, or have a strong presence in the previous games?
gpt
There never were any nightkin on the east coast. They were part of the Master's Super Mutant army, which is the source of the west coast Super Mutants. The east coast Super Mutants come from FEV experiments in Vault 87, and there weren't any nightkin created there.