Crafted as one of the greatest creations of the Necrontyr, it quickly became one of the most powerful servants of the C'tan. During ancient times, its purpose was to bring death to every corner of the galaxy whilst raising black pyramidical monuments to honour its deathless masters. Such acts were conducted on a thousand blasted and ruined worlds. For reasons unknown, it became trapped within its hibernation sarcophagus and became lost onboard the Space Hulk Kronos where it drifted in its sleep for sixty million years.
During the Age of the Imperium, Inquisitor Jena Orechiel led her retinue (including her son, Kal Jerico) to deprive the awakening C'tan of the Setekh. The ancient creation had awoken and had forgotten its great purpose but recognized that invaders had intruded upon its sanctuary thus leading to it taking its wrath against them. After awakening, it had only tapped into a fraction of its power whilst drawing power from its sarcophagus, where it effortlessly killed the Ordo Xenos retinue and members of the Deathwatch with powerful energy blasts. Cyclonic torpedos were later deployed against the Space Hulk where it was believed that the Setekh was either destroyed by being blasted into the warp or sufficiently damaged that it became useless to its C'tan masters.