Prior to uncovering what they really were, we called them "passengers." They're technically tiny parasites in our brain, or rather - they're part of an astronomically huge main body of a parasite that created these shards of itself and they spread across the human race, mutating into a parahuman's offspring.

It's sort of a whole... complicated story that we only very recently uncovered. [That she uncovered and not Lisa, fuck you Lisa.]

Are Crests like, a biological thing then? If it's magic I'm afraid I don't quite know how that interacts with my areas of expertise.