The Bronze Vipers were an 8th Founding loyalist Space Marine chapter. They were tasked to patrol the boarders of Zoragon space, although they also fought Eldar forces as well. As a result they established tactics revolved around Xenos hunting. In M39.204 Eldar craftworld Nirmia destroyed most of the chapter. As the chapter was trying to recover the Zoragons launched an attack annihilating the rest of the chapter.
Ever since their inception, the chapters frequent mutations were a constant thorn in their side, making them very prone to the Red Thirst. This resulted in there being a large amount of those in the Death company, and the Chapter as a whole was rarely at full strength.
Founded in the times of the Nova Terra Interregnum, the Bronze Vipers were assumed to be created to defend the Imperium from threats near the edge of the Segmentum Obscurus. They settled on the planet Sevi, a huge marshland filled with crocodile-like creatures. The planet was on the boarders of space inhabited by the Zoragon species. For many years the Bronze Vipers kept the Zoragons out of Imperial space, but attacks from Craftworld Nirmia prevented them from launching a full scale crusade on the Zoragons.
The Bronze Viper favoured assault and short range fire fights. They were said to strike at the heart of the enemy before spreading to destroy the rest. As a result they had many jump packs and bikes, where they could easily travel to the enemy to engage them in combat.
The Bronze Vipers had a large Death Company, due to the frequent cases of the Red Thirst. They also were often under full strength, due to continued fighting and mutations. The Bronze Vipers had large amounts of assault troops with jump packs or mounted on bikes.
Craftworld Nirmia often sent its troops to try and take Sevi, which was once a Maiden world. The Bronze Vipers at times lost regions of the planet, before retaking them afterwards. As a result the chapter often clashed with the Craftworld, with both sides taking many causalities. However it was the Eldar who eventually prevailed when they attacked the chapter in M39.204