When a truly great warrior of a craftworld falls, their spirit is not always left to rest within the infinity circuit. In times of need a soul of exceptional strength may be summoned forth and set into a spirit stone at the brow of a wraithlord, a striding construct of psychically grown wraithbone. There is no pilot within, only the animating will of the dead hero, roused once more to defend the people he served in life.
The wraithbone from which the wraithlord is wrought lends it a supernatural resilience, shrugging off blows and blasts that would obliterate a vehicle of cruder make. Towering over the Aeldari it fights beside, the construct wields weapons scaled to its size, bright lances and shuriken cannons and scatter lasers, while its great fists can tear apart tanks and monsters at close quarters. It is at once an engine of war and a reliquary, a thing to be honoured as much as feared.
Yet the wraithlord does not wake easily to the living world. Like all ghost warriors it suffers wraithsight, the disorientation of a spirit gazing out upon realspace as a shifting haze of colour and form, and without guidance it may fall still and unresponsive at the worst of moments. For this reason a Spiritseer marches alongside it, tethering the hero's soul to the here and now, so that the mighty dead may lend their strength to the battles of those who still live.