The Bloody Corsair

Fear is their weapon.
Led by unquenchable hatred for the False Emperor, the Lords of the Night roam the Galaxy, sowing terror and inventing new ways to avenge the killers of their primarch. Dark paths lead them to an alliance with the Red Corsairs. But this alliance—secured only by a common enemy—is strange and fragile. Together with these renegade pirates, the Lords of the Night attack the fortress-monastery of the imperial order Adeptus Astartes, aiming to steal geneseed from the Space Marines and doom the order to slow death.