i hate energon, but i am going to try to watch the last few episodes that i haven't seen, starting with ambition, and i read a review on it and it says superion's bro was killed, so there was a fourth combinder, could it have been defensor? edit: will add more after i watch it
Bit of a cop out really, but if it was a new guy, perhaps Defensor, then the fandom would have demanded a toy. New molds are very expensive. I'm still surprised e-Hobby didn't release a Ghost superion giftset. Seems like that would have been right up their alley.