"Anathema's Daughters", an illustration inspired by the Horus Heresy novel "The Master of Mankind" by Aaron Dembski-Bowden. Here's how I imagine a sister of battle at the end of the War in the webway. One of the best HH-books imo, alongside "Fulgrim". Thanks for looking!
EDIT: I was wrong, indeed the sisters of Battle did not exist at the time of the war in the webway. The Sisters of Silence did. I erroneously clumped them all together.