Juju

A juju is a talisman-like object that is capable of performing enchantments and possesses a complex system of rules governing its use. Jujus lack any sort of traceable origin, and some cherubs believe they simply appear spontaneously out of nothing. Each juju exists as a single entity across all realities and cannot be copied or permanently destroyed. Should there ever appear to be two copies of one juju (like a waking version and a dream version), one of the copies is an illusion or error and will eventually be erased from existence.

Calliope and undyingUmbrage have their own jujus, and both want to acquire the other's as well. The jujus have enchanted the anchors that keep Calliope and uu's shared body chained to the wall of their room, preventing them from breaking the chains or removing the anchors. Calliope's juju is an heirloom passed down to her by ancestors and kept in a Juju Chest; she considers it to be the most beautiful thing she has ever seen and wants to give it to Jane, but it will be worthless to her unless Calliope also sends uu's juju.

uu believes that Lil' Cal is a juju and has asked Dirk to destroy it, saying that it and other jujus exist only to ruin the lives of everyone occupying the same universe as them. Since there are Cals on both Earth and Derse, if Cal is a juju one of the two would have to be erased. This eventually occurs when both of Dirk's selves are rendered unconscious and his waking self drops Cal into the ocean, where it will presumably be purged from existence when the Red Miles destroy the post-Scratch Earth universe.