The Axis droid leader was a K3 security droid that had been reprogrammed; it spearheaded the Vanguard Axis in the initial years of the Imperial Era. In the period spanning from 19 BBY to 18 BBY, it crossed paths with the Bad Batch when they brought a shipment of counterfeit chain code chips to the Axis Base space station. Following Omega's discovery that the Axis droids were involved in the trafficking of the Wookiee Padawan, Gungi, and her subsequent attempt to liberate him, the Axis Leader stepped in, only to be shot by Hunter.
The initial glimpse of the Axis droid leader was provided in the second promotional trailer for the second season of Star Wars: The Bad Batch.