The Ciricrux Anima is a forbidden psychic amplification technology first developed during the Dark Age of Technology and permitted for use only by the Emperor's direct command on the Warlord-Sinister-class Psi-Titans of the Ordo Sinister.
In place of the moderati who would normally crew a Battle Titan, a Psi-Titan is instead crewed by the damned: bound psykers who are surgically locked in place and slaved to the will of the psychic Null who serves as the Psi-Titan's preceptor-intendant and who masters the god-engine in place of a princeps.
By direct cortical control, the powers of the slaved psykers are siphoned off and focused by the arcane technologies of the Ciricrux Anima, the baleful device that truly makes the Psi-Titan what it is.
The Ciricrux Anima allows a Psi-Titan to project its suffering internal psykers' powers externally, meaning that a Psi-Titan can unleash waves of abject fear, wield psychokinetic abilities, leech away the life forces of other combatants through biomancy, and even distort the flow of time to heal itself.
- The Horus Heresy - Book Seven: Inferno (Forge World Series) by Alan Bligh, pp. 134 (Image), 282