Whispers (Warhammer 40,000)

When Imperial Missionary Marcus Amouris calls for aid from the Astra Militarum for the savage tribe he is bringing into the Emperor's light, he is dismayed when their saviours turn out to be the grim Battle Sisters of the Adepta Sororitas. Joining Sister Adamanthea and her warriors as they enter the ancient City of Whispers in search of the prey that hunts the tribe, Marcus discovers that the Emperor works in mysterious ways… and so do other, darker powers.

Read it because
It's a look at the Sisters of Battle through different eyes, and a chance to see a part of the Imperial Church we rarely witness – the often dangerous (physically and morally) work of the Missionarus Galactica