Mag'ladroth

Mag'ladroth, the Void Dragon, is the C'tan the others treated as the worst possible neighbour: master of the material, maker of warriors that did not break, a cloud of dark light when it fed on stars. Eldar myth remembers Vaul's talismans spilling the secret that let it be bound.

Szarekh's revolt shattered it. A vast remainder is widely held to sleep under Mars in the Noctis Labyrinth, the Dragon the Emperor is said to have beaten before the Age of Strife and left as a trapped engine. Mechanicus prayers may be aimed at a star-god whether the priesthood likes that sentence or not.

No convenient shard walks the battlefields the way the Nightbringer does. That is not comfort. It is a delay.