Aether's chapter by chapter observations have me thinking and we've had a few talks about the last two chapters of book 1 and such. I never before really considered too much about how if Guyver didn't catch on. So was Guyver III supposed to be a big mystery or were we always supposed to figure it was Agito? I mean I really don't think there was much mystery. I mean I sort of wondered who was Guyver III when I watched the OVA series, which was when I had only seen the two live action movies. Then I went 'oh of course!' around the fourth or fifth episode. Was he supposed to be Agito or very much somebody we had never met and Agito was going to go the Zeus Thunderbolt route sooner rather than later?

I mean if Guyver III was going to be someone in the cast then it could only have been...Agito. Unless it reshaped itself dynamically around Natsuki's form. So either he was super obvious or someone we would never met I have to conclude then Takaya decided to make them one and the same, that's what I think. Glad the 'mystery' only sloshed forward for about nine chapters, I like how the anime series didn't keep it hidden too long.

my main area of focus for this would be the out of control OVA.

that OVA was produced before guyver 3 was revealed as agito makishima.

Agito isn't in the OVA.

from that info, I might imagine that the producers of that show were not aware of GIII being Agito.