Defence of the Gauntlet

The Defence of the Gauntlet was a joint-castigation campaign carried out by a Host of the Astral Warriors and their allies from the Storm Sentinels Space Marine Chapters. Received an astro-communique for immediate assistance, a Host of the Astral Warriors responded to the beleaguered forces of the Storm Sentinels Chapter. Once the Astral Warriors rendezvoused with their Storm Sentinels counsines, both Chapters rallied their forces and launched a devastating counter-assault that utterly decimated the Forces of Chaos. Since this campaign, strong bonds of brotherhood were formed between the two Chapters, and both have sworn to answer the other's call, should the need ever arise.

History
Answering a call for help from the Storm Sentinels, an Astral Warriors Host comes to support their ally and engage in numerous void battles against a Chaos Warband and its slave Chaos cult. After their brave and valiant victory, a pact has been made between the two chapters, with a blood debt sworn and an exchange of one banner from each Chapter.