Hotwire was added to the canon in the 2000's as a Cobra as a convention-only special character. The deranged Hotwire comes from a lineage of Bavarian scientists operating within criminal spheres and he specialises in B.A.T. Maintenance & repair, and is also a bio-mechanical engineer.
As mentioned in the WiP post (you can see the source inspiration and chosen base mini below), I zeroed in on tackling this model mainly based on ease of conversion - the mini is from Studio Miniatures and was immediately obvious as a candidate for reworking for my G.I. Joe Project. However, as I plan to eventually paint up some B.A.T.s (Battle Android Troopers), it makes sense to have a character who can boost them, making it an even better decision to make Hotwire. Therefore, expect to see Hotwire eventually in mine and Brummie's games of Squad Wars at some point. Painting him takes me up to four Cobra characters, so I have a way to go to catch up with my number of Joes and the number of Cobra that Brummie has painted. I have a nearly-finished Cobra Ninja Viper, and a few Joes already part-painted, so with luck a few more minis may get done this week.