Dawn of War II (Warhammer 40,000 Novels: Space Marines)

One Blood Raven and one Apothecary are the only survivors of a mission on Prosperon (now a dead world) to retrieve a relic. Ten Blood Ravens fell. Nine gene-seeds were recovered. Needing to recruit additional warriors to the Chapter, the Blood Ravens go to Calderis, a desert world. Humans and feral orks populate the planet. The Blood Ravens are surprised when the orks attack Argus Township. The feral orks from beyond the mountains have never before attacked the human settlements on this hemisphere. The Blood Ravens launch into action.

Feral orks are not the only problem though. Behind them are developed orks, spacefaring greenskins armed for war, and they have a legendary warlord leading them. Worse, the Blood Ravens within Argus Township are exposed to an unexpected enemy, xenos!