Mazinger Z is a piloted combat robot secretly built by Professor Juzo Kabuto, in anticipation of Dr. Hell's ambition of world domination. Its armor is made from Chougoukin Z, an extremely durable alloy synthesized from Japanium, allowing it to shake off conventional weaponry, as well as the armaments of many initial Mechanical Beasts without a scratch. A Photon Power Engine is installed as Z's power source, utilizing Photon Power generated from the fission of Japanium. Mazinger able to lift, throw, and damage opponents its size or larger, along with using various destructive weapons with the energy provided by the engine. It is even said that Mazinger Z's combat power is comparable to the United States Navy's 7th Fleet.
However, Mazinger Z's Photon Power Engine is not all-powerful - constant usage of Z's energy-based weapons such as Breast Fire, followed by having Z running at top speed over extended periods of time will cause the engine to overload, therefore rendering Z paralyzed, as seen in Z's first encounter against Gerberos J3 in Episode 33. Taking note from this, the professors at the Photon Power Laboratory enhanced the output of the Engine from 500,000 Horsepower to 650,000 Horsepower, which allowed Z to run at top speed for a bit longer, contributing to its eventual victory. Furthermore, Z's Photon Power isn't unlimited; when the Japanium inside Z's Photon Power Engine has reached the end of its durability period, Photon Power can no longer be generated. This will lead to many of Z's weapons becoming unusable, and, at worst, cause Mazinger Z to explode if operated for too long. Simply replacing the Japanium inside Z's Photon Power Engine will solve the issue, though it is a fairly time-consuming task. In Episode 70, during Mazinger Z's second major overahul following the destruction of the Hover Pilder, the Photon Power Engine was upgraded once more, increasing its output to 920,000 Horsepower.
Another issue present in Mazinger Z is that even when receiving occasional repairs after getting damaged, repeated combat will eventually push Mazinger Z's internal machinery to the breaking point, which was shown in Episode 58, when Mazinger Z literally broke down during battle and cannot use any of its weapons, requiring assistance from Aphrodite A in order to defeat Gian F3. The Photon Research Laboratory staff immediately began on overhauling Z after the battle, while also using the occasion to install two new weapons for Mazinger Z: Iron Cutter and Drill Missile. These two weapons notably directly contributed to Mazinger Z's victory in the 2 following episodes.
Mazinger Z was deemed as a "perfect robot" since the start of the series, but with the Underground Empire constantly sending out newer Mechanical Beast models with advanced abilities such as flight and weapons capable of easily damaging Chougoukin Z, the Photon Power Laboratory staff worked hard to upgrade Mazinger Z, with the Jet Scrander or Daisharin Rocket Punch being noteworthy examples. Thus, Mazinger Z became even further perfected to the point that in Episode 85, Professor Watson claimed he could no longer think of anything else to add to the Super Robot.
With its tremendous power, Mazinger Z eventually emerged victorious against all of the Mechanical Beasts and Ghost Mechanical Beasts of the Underground Empire following a 2-year long campaign, with assistance from its robot partners and the Photon Power Laboratory staff. However, with the subsequent emergence of the Warrior Beasts Gratonios and Viranias from the Mycenae Empire following the fall of the Underground Empire, Mazinger Z was rendered powerless and utterly defeated at the hands of these new enemies. After Great Mazinger took Mazinger Z's place as the new guardian of humanity, Z was repaired and retrofitted with the stronger and lighter Chougoukin New Z, allowing it to properly combat the Mycenae Empire.
To activate the robot, Mazinger Z requires a Pilder craft to be docked with its head. After shouting "Mazin Go!" to deploy Z from its hanger, Koji will cry "Pilder On!" and have the Pilder combine with the Super Robot. It seems that Mazinger Z can be remotely controlled from the Pilder through voice recognition to some extent, as seen when Kouji's repeated cries of Mazin Go prompted Z to climb its way out of the damaged pool hangar at the Photon Power Laboratory in Episode 64.
