

Ultramarines
2 books
The Ultramarines series by Graham McNeill has 2 books. Start with Nightbringer (2002), then read the rest in the order below.
Ultramarines reading order

Nightbringer
Graham McNeill
Newly promoted Captain Uriel Ventris of the Ultramarines is dispatched to the Imperial world of Pavonis, a planet plagued by Dark Eldar pirates and a mysterious cult. As he investigates the escalating chaos, Ventris uncovers a sinister plot that suggests a deeper, more insidious force at play, manipulating events from the shadows. Ventris and his warriors must battle not only alien raiders but also treacherous forces within the planet's own defenses, all while racing against time to prevent the awakening of an ancient, galaxy-ending power known as the Nightbringer.

Warriors of Ultramar
Graham McNeill
The Ultramarines, led by Captain Uriel Ventris, face an existential threat as the monstrous Tyranids, known as the Great Devourer, descend upon the strategically vital world of Tarsis Ultra. Tasked with defending this crucial planet, Ventris and his Space Marines must not only battle the relentless alien horde but also confront an ancient oath that binds them to fight alongside other Chapters. This epic confrontation explores themes of duty, sacrifice, and the unyielding resolve of humanity's greatest defenders against overwhelming odds.