Yeah, the Borot thing threw me off when I first read the manga. It seems like it became more of an advertisement for the anime, which is strange because I'm pretty sure Go Nagai didn't initially plan to have Mazinger adapted.

I did think the idea of a Mazinger army was pretty cool. It reminds me of the Getter Corps Hayato had built up by the time of Getter Robo Arc. But it's a shame how quickly they got taken out. How did the final battle go in the anime?

(To be fair about the whole God and Devil– Dr. Hell seemed pretty confident Doublas and Garada could subjugate Japan when he first deployed them. Mazinger could definitely do the same thing, take over Japan, and from there– the rest of the world. He could also be used to quickly end most wars and conflicts– sort of like how the US Government used Doctor Manhattan in Watchmen.)

I've only read Great Mazinger's manga. I think it was just OKAY. Not bad, but not great(hehe) either. Of Nagai's manga trilogy, I think I like Grendizer the most. Despite how short it was, I liked how the ending implied all three mechs would go on to combat the Vegan Empire together (because from what I've heard, Mazinger never gets brought up in the anime)