The Elemental Spheres
  Should a reservoir ever be emptied the yggdrasil conduit joining it to the shrivatsa will shatter during the next purge and that pocket dimension will shatter as well, merging the remnants of the elemental sphere with another that remains or destroy it entirely if it is the last. Alternatively, if the reservoir becomes full it will be ignored during purges.
  The reservoirs are porous and whilst the leaking energy is never usually a serious drain upon the reservoir, the energies leaking across the elemental sphere typically create life and even sentience. These creatures can sometimes harness the energies themselves in a form known as weaving.
  Sometimes the Nu can become trapped in an elemental sphere’s core, feasting on the reservoir of energy until it is completely drained or they are destroyed. Such Nu have been known to show the capability to communicate with and manipulate sentient lifeforms that use the energies leaking from the core.