The Ember

-The consolidated energies of all Asterii souls, shaped into a projectile weapon to be launched by the Worldminds in an ultimate attack against a Chaos God.

-The Ember was unable to kill Nurgle, but apparently remains a toehold of sorts within the realm/being the Archenemy. It is possible that Lazarus encountered this ember in a dream, surrounded and slowly being encroached upon by gargantuan, organic structures shaped similarly to blades of grass. He was able to rejuvenate the Ember's flickering light using his Redressor. In the process, he learned how to use the device's purge protocol more efficiently.

-King Quinque's plan involves creating a larger Ember from the souls spread across the many Worldminds, and launching properly fatal attack against Nurgle.

-Remnants of the psychic attack seem to remain in the Immaterium, as small glowing embers; these residues have some role in containing the entity that powers the Worldmind.Worldmind of Asterion.