The ziivash is like a web that connects all living things (but not undead--they are a null void of cold horror). Everyone has a personal ziivash, which is like an aura, and it can be tweaked and massaged by a Telepath to make them more submissive, or whatever else she wants to do. Egoists alter their own ziivash to augment their power. The universal ziivash has patterns that can be read by Seers. Nomads can alter the positions of things in the ziivash. Shapers can actually drip substance from the threads to create new things (the greatest can even create new worlds with their own mini-ziivash using Genesis). Psychokineticists can burn or destroy threads of the ziivash and even send that destruction into nulls such as undead.
In the place from which Lasair hails, Seers are the most highly respected for their knowledge, then Telepaths for their ability to lead and make peace. Nomads are considered useful for their utility power. Egoists are considered selfish due to the fact that they only buff themselves. Shapers are considered to be filled with hybris and arrogant, trying to be like gods unto themselves (though they have no concept of gods, that's the best way to express the sentiment). Psychokineticists are considered dangerous madmen with no respect for the ziivash or the world. Those of other specialties who grab one or two psychokinetic powers in order to battle undead are fine, but those who specialise in psychokinetics must be destroyers at heart.