Immortis Guard

The Immortis Guard exist for one duty: that the great lords of the Ossiarch Empire do not fall. Hulking constructs bearing dread halberds and shields broad as doors, they read a battle purely as a map of threats to their charge, interposing themselves with terrible economy. Arrows meant for a Mortarch's counselors find bone; assassins find that the wall they slipped past has turned around.

The souls poured into an Immortis are chosen from those who died shielding others: last-standing royal guards, oathkeepers, veterans found beneath the bodies of the people they saved. From such material the Mortisans refine loyalty into something geological. An Immortis Guard cannot be bribed, baited, or frightened; it can only be destroyed, and destroying one merely reveals the next shield already moving into place.