Mazinger Z mainly takes after his previous incarnations in appearance featuring the same frame and equipment. In the first chapters, the Pilder featured a brain that would allow the Mazinger to move on his own when activated, but after Koji crashes into the craft he literally becomes a part of the brain.
When Mazinger Z assumes his Mazinger ZERO state he assumes a more muscular human-shaped form. The mouth grill turns into a more skeletal-like state with a mouth that can open or close. The eyes also gain noticeable pupils when looked closely, the forearms gain blades attached to them, and the heat sink on the chest becomes sharper. The Jet Scrander on its back also transforms into a large slashed zero symbol on its back that can change forms.
As a robot made from Super Alloy Z - an alloy far stronger than diamond nanorods - and equipped with a Photonic Energy Engine - an engine that can easily produce a total amount of energy equal to the Sun - for a power source, Mazinger Z is very strong and durable. In Mazinger's initial appearance, he featured a mechanical brain that would have allowed he to move without a pilot before Koji was integrated into it. In the current timeline, he is piloted through the use of a Pilder. Mazinger also has a spirit existing in the subconscious of Z’s frame. Z’s spirit keeps a righteous sense of justice as he imples that he will smite evil with Koji. Z sometimes joins Koji’s speech and encourages him to finish Dr Hell, let alone scream “Photon Power Beam!” with Koji. In Super Robot Wars V, this spirit refers himself as Mazin, or “possibility” itself. The Mazin entity manifested when ZERO was affected by Shin Getter Robo’s Getter Rays, liberating Mazin from ZERO’s influence. This entity talks to Koji on why Juzo built Z, how Koji might become a part of Z if he believes he was, and at the end, agrees to fight alongside Koji to experience a “greater power” Mazin would get if he fought with Koji together.