Bashbreaker is a Mini-Con who once worked with the Decepticon Scavengers.
Bashbreaker and his fellow Mini-Cons were captured by the Decepticons in their youth and experimented on. Given the ability to combine with their larger brethren, the Mini-Cons were stored in a laboratory in Darkmount until Starscream stumbled on them. They managed to escape Starscream and fell in with some scavengers so they could escape Cybertron, only to find their new hosts were heading for Earth. They set about trying to work out a way to abandon the scavengers and leave the planet.
In Mighty Big Trouble, the Mini-Cons accompanied the scavengers to an automated ship to find a relic, though Bashbreaker stayed on deck with Paralon while the other scavengers headed for the seabed. After the scavengers managed to retrieve the Dark Star Saber, Bashbreaker and his companions stole their sub-orbital craft. Detecting a power source capable of getting them off-planet, they invaded the scrapyard looking for it, only to be told it had already been destroyed.
In Mini-Con Madness, their craft eventually ran out of fuel, but they ran into the Autobots again, and after Aerobolt recognized Optimus Prime, the two groups teamed up. During an ensuing fight with the scavengers, Bashbreaker and his companions were snatched up by Starscream.
In Worthy, Starscream attempted to merge with the Mini-Cons, only for it to fail because Tricerashot was missing. He was eventually able to obtain the last Mini-Con and merge with all seven Mini-Cons. them all, however Fixit was able to activate a signal and separate Aerobolt. Aerobolt found Optimus and linked with him, providing the Autobot leader with a power-up that let him go up against the super-powered Starscream. The super-powered Starscream dueled with Optimus until he was able to be lured into range of Fixit's signal, which separated him from the Mini-Cons. Bashbreaker and his fellow Mini-Cons left Earth on the sub-orbital craft, now modified by Fixit for space travel.