Are chasmfiends related to Thunderclasts?
No. Good question though. Thunderclasts actually show up pretty early in the second book. More what thunderclasts are — Dalinar sees one in a flashback in the second book. So you’ll get a good explanation of where they come from, but they are more related to the voidbringers where chasmfiends are actually a living part of the ecosystem
So what is the purpose of the pupating?
You will find out. Shallan is asking that very question.
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