The Mazinger Army in the so-called Mazinger World is a squad of robots under the employment of the Photon Power Laboratory composing of Lori & Loru with their Million, Shun Azuma with his Baion, Masao Oide with his Daion, and Sayaka Yumi with her Aphrodite A. With the revelation of Koji with his Mazinger Z, they mainly act as back-up units.
We first see the Mazinger Army battle the Mechanical Beasts in the first arc with Koji still getting used to Mazinger Z. When Koji got the Z they work together to stop the Mechanical Beast invasion. However when Juzo dies from an injury caused by Baron Ashura's troops, Koji tries to kill Ashura only to be held back by the Mazinger Army hoping to capture him. But that fails and so Koji and the Mazinger Army go on bad ends.