Background
The original organization that would eventually become Brimstone Battalion was not a Helldiver Formation but instead was designated as the 1450th SEAF Observation Brigade. The Brigade primarily operated as a colonization security force made up of volunteers who served within one of the sectors that would eventually fall under "Bug" control around the year 2045. The 1450th would eventually be organized into the 105th Defense Brigade after SEAF Command reshuffled its forces to counter the new threat.
From Security to Special Forces
Over the years, the near-constant warfare and attrition-focused battles against the Bug menace quickly formed the Brigade’s fighters into hardened veterans who were used to both killing and dying without much in their hands. Their dedicated service in the face of unstoppable odds regardless of the horrific losses they suffered made them the perfect source to pull a new Helldiver Formation from as the First Galactic War's attrition was amassing faster than expected.
Establishment of Brimstone Battalion
Quickly moved in and out of Helldiver Special Operations Training, Brimstone Battalion was officially established in 2058 as a rapid response Battalion within the Chiron Regiment (56th Helldiver Corps). Specializing in high-risk operations against alien threats, Brimstone primarily focused on scorched-earth missions to counter the neverending spread of the Bugs, but would eventually absorb other Companies to develop counters to both the Cyborgs and Illuminate threats.
The Misfits of the Corps
These absorbed elements were considered by some to be the most troubled elements of other Regiments within the 56th Corps, though in later years the Battalion would also pull Troopers from external organizations that SEAF Command had deemed problematic. This would include at times the reassignment of whole Companies and Platoons to the Battalion, with the hope that their unorthodox and sometimes unstable approach to warfare would combine with their already suicidal tendencies to completely negate the chances of broken morale or an inability to complete missions that were at times “unethical” or had the likely chance of high casualties.
Modern-Day Brimstone
The current state of Brimstone Battalion follows the methodology of its honorable predecessors with its focus on bringing the enemies of Super Earth to their knees through grueling attrition but remaining honed towards a purpose, as reflected in their new motto - T.A.R: Tactics, Adaptation, Retaliation. Its ranks are now filled with the problematic youths of the new age, many of whom are the direct descendants of the original veterans of the Battalion who survived into old age, though outweighed by new blood.
They now all share in a rich history of honor and sacrifice, the symbols of those who have passed away remaining as examples for the new war. A new chant can be heard from Destroyers orbiting the skies above a volcanic planet now serving as the cemetery for all Brimstone Battalion troopers:
“From the bones of those before us, we rise, to spit pitch and flame!”