various
Treacheries of the Space Marines

Even among the superhuman warriors of the Adeptus Astartes, there are those who turn their backs on their brothers. This collection of short stories from the 41st millennium tells tales of some of these traitors and renegades.
Warhammer 40k
anthology

It contains:
The Long War
Vox Dominus
The Carrion Anthem
Throne of Lies
Torturer's Thirst
Bitter End
We Are One
The Masters, Bidding
Liberator

Also in:
Eye of Terror