Lord-Exorcists are Stormcast Eternals that were once holy men that performed miracles and rites of abjuration using magical hexagrams, spirit fetishes – or even through the sheer force of their belief to fight the enemies of Order. Since their reforging their powers have been magnified tenfold and have mastered channelling celestial energy to banish daemons and gheist. Even Nagash despite his towering arrogance have taken note of these figures. 
Lord-Exorcist are responsible for banishing Daemons and Gheists which they do with carefully intoned phrases of power. In combat Lord-Exorcists can send out a wave of crackling null energy by slamming the heel of their ceremonial staves upon the ground which can banish a soul from its body and drive it far into the wilderness.
It is also their duty to judge the lost souls released from the bodies of enemies in the battlefield. They use their Redemption Staves to drag souls and judge the. If it can be rehabilitated it is sent to Azyr so the long process of redemption can begin but if found wanting it is forever banished to the aether. However it is said the number of souls redeemed in such a way number less than the total number of Lord-Exorcists in existence. 
Each Lord-Exorcist carries a Redemption Stave which acts both as a weapon and a rod of office. Upon the stave is a Redemptor Casket which is lined with celestium slate. When it is opened it can draw a spirit in and seal it inside. There the soul is judged by the strange scales atop the cache which weigh the soul.
- 1: Battletome: Stormcast Eternals (2018) - Lords of the Host, pg. 64-65
- 2: Battletome: Skaven (2019)
- 2a: Rise of the Under-empire - pg. 20
- 3: White Dwarf Vol 3 No 36,
- 4: Lord-Excorcist product description
- 5: Warscrolls