Mazinger Z is a fan-film by Spadoni Productions detailing the beginning of Mazinger Z detailing of how Koji first got Mazinger Z and fought the Mechanical Beasts.
Koji Kabuto finds his grandfather dying from the rubble of an explosion. Juzo gives his grandson the Hover Pilder to fly and activate Mazinger Z. When Mechanical Beasts Garada K7 and Doublas M2 attack the Photon Power Laboratory with Sayaka Yumi and Aphrodite A unable to do anything, Koji and Mazinger Z fend them off. Koji agrees to work together with Sayaka and her father against the Mechanical Beasts.