Lesser Evils is a short story by Toby Frost. It was first published in Hammer and Bolter 13, under the name Tom Foster, and re-published online in May 2014.
Lucan Vaughn and his Inquisition task force, veterans of a hundred battles, descend upon the world of Rand XXI on a mission to seize an important asset for their mysterious master. But this mission will bring them into conflict with another branch of the Imperium, for their target is a captive of the Adepta Sororitas, the pious Sisters of Battle. Infiltrating a convent-prison, Vaughn and his team must struggle with the idea of fighting other servants of the Emperor if they are to survive and achieve their goal.