Tesseract labyrinths are fist-sized cubes of necron design that are capable of imprisoning beings of pure energy. A simple push-button interface is used to engage the device's zero-point reactor that enables them to imprison targets within their chambers.
During the War in Heaven, the Necrons turned against the C'tan in the closing stages of the conflict which saw the star-vampires shattered into C'tan Shards. These Shards in turn were bound in the confines of a tesseract labyrinth.[2a] The Necrons are reluctant to field these shackled C'tan in battle and it is a dark day whenever they release them from their imprisonment.[2b]
The Grey Knights were contacted by the mysterious creator race of the labyrinths, who provided a number of these cubes for their use. In this time, the Chapter had determined that they functioned perfectly on Daemons of the Warp though only lesser members of their kind had been successfully entrapped, who were later imprisoned in the Sanctum Sanctorum. Only a single Greater Daemon has ever been trapped by these devices, though it is hoped that it can be used as a means of achieving a lasting victory over the Daemonic threat. However, the Grey Knights have replaced the scientific methods used in their activation with arcane pentagrams, chants and sigils to awaken the labyrinths. Furthermore, relations with the cubes' creators has deteriorated to the point of hostility, which means only a few tesseract labyrinths remain in the Grey Knights' possession, as their Techmarines are unable to replicate the technology.
After the opening of the Great Rift, Occam the Untrue and his Alpha Legion war-band were tasked by a mysterious Necron cryptek to steal from the Daemon World of Ghalmek a tesseract containing Kar'Nash'gahar, Lord of Glorious Slaughter and Slayer of Worlds, a powerful Greater Daemon Khorne.[3a][3b] Occam freed the Daemon and used the tesseract to trap a C'tan Shard of the Deceiver.[3b][3c]
Codex: Grey Knights (5th Edition) marks the first appearance of the tesseract labyrinths and mentions them being created by a mysterious alien race. Codex: Necrons (5th Edition) later shows that the Necrons are capable of creating them and are users of the technology.
- 1: Codex: Grey Knights (5th Edition), pg. 11
- 2: Codex: Necrons (5th Edition)
- 3: Sons of the Hydra (Novel)