Nightbringer

"Newly promoted to the captaincy of the Ultramarines Fourth Company, Uriel Ventris leads his warriors to the world of Pavonis, where vicious alien raiders are bringing death and destruction. As Pavonis descends into political turmoil, Uriel and his warriors must battle the xenos as they unravel a plot to unleash an ancient evil buried deep beneath the world--the mysterious and deadly Nightbringer. This edition also includes the prequel short story "Chains of Command". Locked in battle with the treacherous Night Lords, Captain Idaeus and his warriors--including Sergeant Uriel Ventris--enact a dangerous plan that goes against the tenets of the Codex Astartes ... with deadly consequences."--Publisher website