>>23393149
Mazinger Zero was created by Dr. Blade, he alongside Juuzo created Zero and Z to rake over the world but Juuzo gave up on this idea.

This manga came out in 1997, before Shin Mazinger Zero, that features Mazinger ZERO

Which is funny because in the Shin Getter robo OVA prequel written by Imagawa, there was also a change getter zero that never appeared elsewhere