Defence of White Reach

The Defence of White Reach was an Imperial defensive campaign conducted by the as yet unnamed Dawn Guardians Space Marine Chapter, a newly created Chapter of the Ultima Founding and comprised entirely of newly revealed Primaris Space Marines. This campaign took place upon the Imperial world of White Reach, which had fallen to the predations of a massive invading force of several Chaos Warbands, following the formation of the massive tear in reality known as the Great Rift.

Background
As the 41st Millennium came to a close, a massive invading Force of Chaos, led by the vile Warmaster of Chaos, Abaddon the Despoiler, assault the vitally important fortress world of Cadia during the 13th Black Crusade. Despite the valiant defensive efforts of Imperial forces, the planet ultimately falls. With the destruction of the planet, the veil between the material realm and the Immaterium ruptured and tore, from one edge of the galaxy to the other. This formed a massive tear in reality known as the Great Rift. With the way open, the forces of Chaos and their daemonic legions sallied forth and attacked thousands of imperiled planets that had been cut off by the tumultuous warp storms and the massive tear in reality.

One such world was the Imperial planet of White Reach, which came under attack by a horde of multiple Chaos warbands. Though the warbands are powerful, they faced the mighty Imperial forces of the Indomitus Crusade, led by the returned Ultramarines Primarch Roboute Guilliman, now the acting Lord Commander of the Imperium. White Reach saw its salvation in the arrival of massive Imperial fleet of the Indomitus Crusade, which proved mightier than the invading Forces of Chaos, and soon they drove away the vile Chaos warbands from the surface of the planet.