Clash of Trident and Hammer

The Clash of Trident and Hammer is a lamentable inter-Chapter conflict that took place between the Astral Leviathans and a company of the Hammer Guard Chapter.

Background
As the Hammer Guard's 3rd Company pursue any trace of their wayward kin and engage the Forces of Chaos on numerous battlefields, they come into contact with a detachment from the chapter known as the Astral Leviathans - both are enroute to engage the same foe on the same planet. The two forces meet and the Astral Leviathan's take command, despite protests from Legate Azrael, believing the decision of command should be more carefully thought out. Reluctantly, the 3rd Company goes along with the Leviathans, and descend to the planet, finding the 7th Solaritus Siege Regiment to already be on the planet. The Hammer Guard and Leviathans fortify defenses and overwhelm the enemy, despite what Legate Azrael believes are tactically wasteful orders, especially for the mortals they fight alongside. This uneasy relationship would worsen towards the end of the campaign, however.

On one assignment, a patrol detachment of Hammer Guard and a patrol detachment of Astral leviathan Deunde are sent to aid guardsmen with an unyielding spot of Chaos resistance. As they put down this resistance, one of the Astral Leviathans' initiates seemed to fall into a trance right alongside the Hammer Guard Evocatus supporting them, and tear into the guardsmen. Before the horrified eyes of the Evocati, the initiate ripped through the guardsmen, and turned on the Evocatus squad, forcing them to put him down. The Astral Leviathans' Deunde sergeant then opened fire on the Evocatus squad, and the situation only seemed to escalate. Soon the Hive had turned into a battle ground as the fearsome 3rd Company stood off against the Astral Leviathans, with unlucky guardsmen of the 7th getting caught in the crossfire.

Soon, even the entirety of the Astral Leviathan's were in-system, and the 7th were ordered to fire upon the Hammer Guard. They refused, knowing the Hammer Guard as the saviors of Solaritus, on multiple occasions. This refusal cost them their lives as, to the horror and anger of the Hammer Guard, the entirety of the 7th was slaughtered by the Leviathans. Their response to this massacre was to call in the rest of the Hammer Guard, and the system erupted into war. This only ended when the Hammer Guard retired from the conflict and took the corpses of the officers of the 7th from the system, believing the entire conflict to be a stain upon their honor, a shameful mark on the Imperium and, ultimately, a step backwards on the path to redemption. They never forgot the interaction, however, and the Hammer Guard will no longer enter the same system of the Leviathans.