Since the ancient times of the Great Crusade, the Ultramarines have fought at the forefront of the Emperor’s armies. Highly disciplined and courageous warriors, the Ultramarines have remained true to the teachings of the holy Codex Astartes, the greatest work of their Primarch, Roboute Guilliman, for ten thousand years. Tales of their victories are told from their homeworld, Macragge, to the sacred halls of Terra. Whenever the enemies of Mankind threaten the Imperium, the Ultramarines stand ready to fight them.

COMBAT DOCTRINE
As befits the Chapter of Roboute Guilliman, the Ultramarines adhere rigidly to the tenets laid down in the Codex Astartes. For ten thousand years they have fought in the manner described in its holy pages. Other Chapters may freely interpret the words of Guilliman but, to the Ultramarines, such deviation is unthinkable. The Codex Astartes is a work of divine wisdom, sanctified by the Emperor himself, and the Ultramarines see no reason to deviate from its wisdom. The life-long lessons of discipline and self-reliance that are taught to the people of Ultramar from birth give them the strength of character to hold true to teachings over ten thousand years old.

For any given tactical situation, the Codex has hundreds of pages devoted to how it may be met and overcome. Each warrior of the Chapter is required to memorise whole sections of the Codex so that within a Company there exists an entire record of the Codex’s tenets. The wisdom of thousands of Imperial warriors have contributed to the Codex, and details on everything from unit markings to launching a full-scale planetary assault are contained within its pages.