Talk:Season Four/@comment-4554525-20160608085354/@comment-27794543-20160616040545

Before s3, I would have said there could be people all over the world. The Becca story makes me question that.

Becca made some sort of injections. It's not absolutely clear what these shots did. They may have just given Nightblood, thus allowing the Flame. They might have been an anti-radiation cure. Popular fandom theory is that the injections did both. (Though Nightblood is not inherited by all children and seems to pop-up randomly in the population.) If the injections were an anti-radiation cure, then all Grounders derive from Becca's clan. Sure, over 100 years, people have split up, be banished, become nomads, etc. But essentially all Grounders came from one group based in the Eastern US and there is only so much movement in >100 years.

It's possible that there is more groups like the Mountain Men, but the series can only use that plot so much. It's also possible that Becca was not the only genius, thus other groups invented an anti-radiation cure. So of course, everything is possible.

Also, Emori mentioned that she had other customers for tech ... thus the theory of another technologically-advanced group ...