A Canoptek Sentinel is a Necron robotic construct tasked with containing the raw elemental energies of a Transcendent C'tan that is held captive within a Tesseract Vault. The Canoptek Sentinel draws on the potent C'tan Shard's own energies to erect a force shield around the Star God that keeps it contained within its arcane prison when its Necron masters unleash a Tesseract Vault upon the battlefield.
These Transcendent C'tan, nothing less than the amalgamation of dozens or even hundreds of lesser C'tan Shards, are of such size and indomitable will that they are too powerful to be contained within the extradimensional intricacies of a Tesseract Labyrinth, and a Tesseract Vault serves as both a prison and a conduit for their power instead. Bound within the vault’s heart, the star vampire will fight against its bonds; and such is the elemental might of the C'tan that the walls of the Tesseract Vault are perpetually being destroyed by the insane energies the Star God generates. It is only the unceasing ministrations of the ever-vigilant Canoptek Leech guardian constructs arrayed and docked around the exterior hull of the Tesseract Vault that keep the C'tan in check; these, and the robotic construct known as a Canoptek Sentinel that encloses the C'tan itself in a force shield held together by eight writhing, mechanical tentacles and generated using a portion of the C'tan's own power. However, there are only so many Scarabs and Canoptek Leeches holding the Tesseract Vault together, and as the Transcendent C'tan bends reality and tears metal off the vault in its bids for freedom, the Canoptek automatons rebuild its prison using the debris in a cyclical process of destruction and reconstruction.
- Apocalypse (6th Edition), pp. 170, 173
- White Dwarf 404 (July 2013) (AUS), pp. 10-13, 144-145