Mazin Battle

Mazin Battle is a spin-off manga by Takafumi Adachi and published in Dengeki Bazooka starting on July 21, 2015. Other robots under the Dynamic Productions brand such as the Getter Robo are also stated to appear.

Summary
One day out of the blue, a mysterious robot called the Mazinger Z appears crashing down on top of a rooftop with a boy named Gai Todokuna meeting the robot and guiding him in battles taking place.