The Exorcists are a Space Marine Chapter unlike any other. To combat the forces of Chaos, they willingly accept daemonic possession, knowing that once it is purged their shattered souls will no longer be susceptible to corruption. Those who fail the banishment trials become Broken Ones – living prisons for the terrors expelled from their brethren. Should such desperate measures become known to the wider Imperium, the Chapter would stand accused of the vilest of heresies.