kazoo

Maybe it possesses the same traits of spren, such as bonding and an affinity for stormlight. Agreed that it's speculation but I like the idea! Maybe they are more akin to Ryshadium instead of spren, the more I think about it. Both seem to bond to a human and possess supernatural talents.

Thanks for the responses guys. I like that idea! Except maybe as Leuthie wrote, it is the spren that allows them to change forms. Agreed that it's unusual to find rare gems within living creatures and that it's more unusual that they are always (so far) completely infused with stormlight Hypothetical: if they are able to change forms, would the size of their gemheart change with each transformation? Maybe a better hypothetical question: what comes first, gemheart or spren (if indeed a spren does bond with chasmfiend)? You think the gemheart exists before their bond with a spren? Thought that spren can only bond with sentient beings (no source, just an understanding I thought I had of this world)? I feel the stormlight that larkins absorb must do something...don't have the book near me at work but I don't recall reading about the larkin glowing after it absorbed the stormlight from Lift.

Do we know how chasmfiends develop their gemheart? What happens with the stormlight that larkins absorb? Does it concentrate within the creature and solidify into something concrete? I know that's a lot of questions but I was just wondering if anyone had ideas about this.