The Nucleus, or Nuclei in its plural form, is the collective of a person's metaphysical composition. It is commonly and incorrectly referred to as "soul", despite the fact that the soul is in fact part of the Nucleus. It seems to possess some remembrance of its original body, as immersion in Eitr can restore the original form of the Nucleus's former owner. Physically materialized, the Nucleus takes the shape of a hexagonal bypiramidal crystal. The organisation known as the Consortium kept a large collection of Nuclei within a citadel in the abandoned Atlantean city of Varandiil Aanor.