|Power Source||Atomic Energy|
|Dimensions||Height: 100 Meters|
Giant F3 true to its name stands 100 meters tall, making it several times the size of most robots in the series including Mazinger Z itself. Compared to the more human-shaped or animal-like Mechanical Beasts, Giant F3 has a tank-like lower body with treads that allow it cross most terrains. It has long flexible arms and scooper claws for hands. It's long human-esque face is white with yellow accents and a red nose.
Abilities and EquipmentEdit
Giant F3's large height is its main form of defense and offense, this grants it higher strength than most robots its size. To move around, Giant F3 uses its tank treads. It is also capable of moving through large bodies of water like the Pacific Ocean. Its armor is highly resistent to projectiles. For offense, Giant F3 uses its arms and toothy scooper claws to attack along with heat rays from its eyes.
Dr. Hell used this robot to help build more defense around his fortress along with Titan. While it uses it claws to dig it accidentally dumped a huge pile of dirt on top of Dr. Hell & Baron Ashura. When Count Brocken's Iron Cross fail to kill Koji Kabuto yet again, Dr. Hell sent the two giant Mechanical Beasts to destroy him. When it reached the city, Aphrodite A came up to stop him but was no match and Giant just threw her around like a toy. Koji and Mazinger Z came to the rescue to stop this gigantic monster. While its size proved to be an advantage, as Rocket Punch had no affect, its armor was still too weak to stand up to Mazinger's Photon Beams. As such one arm was blown off and thrown right back at him. After Koji manage to shoot down one of Giant's treads Mazinger somehow malfunctioned and was unable to destroy the other. Sparks fly from Mazinger as it was unable to move because of a magnetic force.
- It appeared in Tranzor Z under the name "Leviathan".