Warhammer 40,000 Legends Collection: SEALED hardback novel - 

Ravenwing by Gav Thorpe, Issue 24, #31

"The Ravenwing stand apart from the rest of the Dark Angels Chapter - these dynamic Space Marines take to the battlefield upon steeds of adamantium and steel, and swoop from the skies in lightning-fast speeders to bring death to the foes of the Imperium. Led by the heroic Master Sammael, they prosecute war where their battle-brothers cannot, and are ever at the forefront of the Dark Angels' campaigns."