In orbit above the planet, Captain Severus departs the cruiser with only the Ultima Squad, highly eager to prove themselves in battle, for support. With the ceremony finished, Ultima Squad prepare themselves for their first mission-a sortie to the planet of Mithron. The Captain and his right-hand man, Apothecary Pythol lead the initiates in a swearing-in ceremony on the Hammer. The members of Ultima Squad are then shown a sacred weapon in their ship's reclusium, a Relic Thunder Hammer. Proteus manages to disarm Severus, however, he quickly escapes Proteus's grasp and in turn defeats him, proclaiming that a Space Marine never yields. Elsewhere, aboard a Space Marine Strike Cruiser, Brother Proteus and Captain Severus of the Ultramarines Chapter spar in a training duel. A Space Marine by the name of Nidon is told to protect 'the Codex' and races to obey his orders, just before a fireball engulfs them all. The film opens with a group of Space Marines of the Imperial Fists Chapter under attack from an unknown enemy.

Space marine strike cruiser