The minds sharing Lucia Mar's body, waiting in a cold dark room and taking turns at the surface.
Under compulsion to tell the truth, Diah describes them: they are in the dark, and it is so cold. Sometimes they can hear them talk, hear them whispering — "like a river running through our room, and if you touch it, it hurts." The whispers say things.
When the dog wanders off, Lucia Mar fades and one of them takes over, and they see again. They take turns. Sometimes it is day, and they see light. Carl hears this and thinks only "holy shit," and it is enough to make him cancel the death mark and confirm what Florin had believed all along. Lucia Mar's parting warning — that killing her would kill all the children of Earth — reframes them as hostages on a scale Carl cannot yet measure.
The hidden population inside Lucia Mar whose existence makes killing her unthinkable.