So I didn't know whether to post this in tg or in tf since it is a mix of both, but since the TG forum didnt have a thread like this i decided to post it here.
I randomly found a vid of an older game Devil May Cry 2 where the final boss has both a female and male form. In the given cutscene, it changes from an amorphous blob into a female flame demon, then to a male one. Not to much to see since they are literally fire, but you can certainly tell the shift from female to male.
https://www.youtube.com/watch?v=8PLpKRTr6lk&t=6s
Also, this can be the start of the same thread that the TF forum has, except for this one, if you guys would like.