I guess we're skipping over Ganishka's apostle form to whatever he's going to achieve due to the reincarnation machine. Daiba states that Ganishka's very body is made up of the fog, but the general opinion here is that's not his apostle form, but an ability he had before being reborn.
Yeah, if he had an apostle form we've lost the chance to see it now, or at least to see what it was before the upgrade. However I think the "general opinion" like you say is more that his fog is magical in nature as opposed to simply being his apostle form, as several things have hinted so far. Whether he acquired at least some of those magical abilities prior to becoming an apostle or not is impossible to tell IMHO (I'm sure that becoming an apostle would have dramatically increased his aptitude though).
Concerning Daiba's comment, it could be that Ganishka's body actually dissolved once in the apostle-cauldron, leaving him with a practically pure astral form. Another possibility that I'd thought about before is that the fog could have been his real form from the first time, his human form being something he had to materialize willingly. That could explain why when Griffith showed up he could coerce him into transforming into fog, how he managed to transform instantly when Irvine shot him in Wyndham, or why he was literally fuming at the beginning of this episode. Could be the result of experiments he had conducted on himself over the years in order to augment his power, maybe that even cost him his actual apostle form (
heavy speculation here). However a few things make me think this isn't the case, for example the fact he was physically seated in his room with a giant scar on his face after Guts & Zodd dispelled his cloud form, or what happened when the strong wind blew his fog away during the battle of Vritannis.
Just a side note, but I remember that in the last episode thread, becchii was wondering why Griffith had bothered sending a dream to tell the people in Wyndham to shut themselves in, then to flee the city, etc. Of course now we know what danger they were facing, but I think this also brings the purpose of warning them into a new light. If they hadn't been hiding and had fallen prey to the fog, they would have been more potential power for Ganishka. So not only is he saving their lives and preventing them from seeing what's going to happen in the city, he's also making the incoming fight easier for himself.
I'm really hoping we get some back story on the Emperor of Terror, to see what his life was like before using a beherit. I wonder if he was the Kushan Emperor before he became an apostle, or if he started building the empire afterwards.
Yeah, same here, a backstory would really be appreciated. It'd be interesting to see how the empire was formed, why the Bakiraka fell into disgrace, and why not even some of Rakshas' own backstory if he had met Ganishka before ("who stole my beherit?!").
Anyway, for what it's worth I think he became emperor after acquiring his powers, uniting all the clans together under his banner.