The psion is an extradimensional elemental particle with a number of strange properties:

  • It can act as a particle or a wave.
  • It can temporarily mimic other elemental particles or waves.
  • It can “latch” onto elemental particles and modify their properties or behaviour.
  • It is attracted to, and can be guided by, analytical machinery. This includes animal brains as well as partially or fully self-aware AI.
  • It is not bound to our laws of physics and can defy them.

Although psions spontaneously appear and disappear at a minuscule rate in nature, this rate is modified by the amount of analytical machinery in any given place. Warpstone, besides its chemical properties as Uranium-259, acts as a psion emitter, altering regular environmental readings and, hypothetically, inducing otherwise impossible changes in nature, space-time, and perhaps fate itself. Currents of high-energy psions are readable by psiometres (specialised measurement tools) and are denominated psionic energy.

Psions and their interactions with realspace are the basis of Psionic Theory. Psionics as a field of science officially came to be as part of Project LIBERTY's research into U-259.