Ferra/Torr And Possible Inspirations?
When I think of Ferra/Torr the whole duo is not anything so new but it is among the list of unusual playable characters. You might consider some past video game characters or two, Master and Blaster from the Mad Max movie. For me, the duo reminds me of Luna and Amok in the Thundercats series considering Ferra is a female and Torr is a male.
Chang is a playable character in King of Fighters where he had his tiny partner Choi who he can use as an assist partner in Capcom vs. SNK 2 though back then, Choi was just a spectator. The concept was also used in Marvel vs. Capcom where Megaman had Rush all the time in battle. Though the whole similarity is with Chang and Choi since Choi was the the brain, Chang was the brute force and main player and the same can be said for Ferra/Torr. Torr is the main player while Ferra rides on his back, she's not even killed during the time fatalities are done on the opponents.