Talk:Mountain Men/@comment-35300790-20180414030635/@comment-850810-20190806145844

The Sky People were in space and exposed to solar radiation for nearly a hundred years. They evolved to withstand it. The same basically happened for the Grounders though we know some got mutations from it. The Mountain Men have no immunity because they remained completely underground and isolated from the radiation. They were never exposed so they never developed an immunity over time or at least tolerance because we know that higher levels of radiation are still fatal to Sky People and Grounders.