Marvel Comics continuity
Brawn was part of a team led by Hot Spot, and including Skydive, Steeljaw, Override, and Chase, sent to answer the distress call sent out by their human allies G.I. Joe. They arrived in Millville, just in time to save Scarlett from a recently revived and Cobra-upgraded Megatron. Brawn and the other Autobots quickly learned that Megatron's strength and weaponry had been vastly improved. First Steeljaw fell, then Chase. Finally, it fell to Brawn to keep Megatron from reaching the Autobots' ship. Though Brawn fought Megatron bravely, he was vaporized when Megatron revealed that he could implode neutrons. The resulting explosion was seen from across town.
Devil's Due G.I. Joe vs Transformers continuity
Alongside several other Transformers, the dormant Brawn was found aboard the crashed Ark by Cobra. Cobra reprogrammed their findings for their own needs, rebuilding Brawn and Gears into Cobra Flight Pods in the process. Two Flight Pods were later seen during the Cobra attack on the SPS Research Facility, but they didn't transform, so it's unclear whether or not they were Brawn and Gears. The reprogramming was eventually undone by Wheeljack, and Brawn and Gears quickly located their former captor, Cobra Commander. Destroying the human's escape route, Brawn made it clear that he was not interested in negotiating and that he'd rather have laid to rot aboard the Ark forever than be used as Cobra's servant. Unfortunately, Storm Shadow came to Cobra Commander's rescue with a S.N.A.K.E. mech and knocked the Autobots out before they could capture him. Brawn was later shocked when he heard that the United States military were nuking Cobra Island.