King Godzilla is a fusion of King Ghidorah, Godzilla and Battra. Instead of his arms, he has King Ghidorah's left and right necks and heads. His body is preserved from Godzilla, but his legs are from King Ghidorah. Finally, he has Battra's wings and brain. King Godzilla is also fatter than his normal counterpart, and has a more pronounced breastbone. If King Godzilla's chest is destroyed, he reveals that he actually has a fourth component, being Biollante's DNA. This manifests in the form of her head, which he then uses to fire a powerful jet of sap from his now-repaired chest.
After having almost all of his kaiju destroyed, Dr. Oniyama combined DNA which he had harvested from Godzilla's cells with DNA from King Ghidorah and Battra, and then used a growth medium to encourage development of the new creature, dubbing it King Godzilla. He then unleashed it upon Japan, with Oniyama personally riding atop his new creation. Godzilla, although brutally weakened from his near constant battles with Oniyama's legion of monsters, came to fight King Godzilla on the side of a volcano. Godzilla was horrifically injured by his far superior clone, but managed to rip off one of King Godzilla's Ghidorah-hands. Eventually, Godzilla was lifted into the air by King Godzilla and dropped mortally wounding them on a bed of spikes set out by Oniyama, forcing Machine G to fight alone. Machine G mobilized with the G-Team, using its twin masers to deal devastating damage to King Godzilla. Machine G managed to rupture King Godzilla's chest, but then the kaiju unleashed its most powerful weapon yet, being the head of Biollante! He then slammed into Machine G and attempted to destroy the mech by stomping on his head, but he was grabbed by the mortally wounded Godzilla, Allowing the mech to escape. Machine G used his weapons from afar, and Godzilla then reappeared. The duo collaborated to destroy the Biollante Head, giving Godzilla the advantage. Godzilla managed to fling himself and King Godzilla into the volcano. Godzilla, his clone and Oniyama all burned to death inside the volcano's magma.
- King Godzilla can fire Gravity Beams from his Ghidorah hands, and do so in tandem with his atomic breath.
- King Godzilla can lift things equal to or greater than his own weight, including other kaiju such as Godzilla.
- King Godzilla can fly using his Battra Wings and slam into opponents.
- If King Godzilla's chest is critically wounded, he will repair it by growing the head of Biollante. This head can fire an incredibly powerful burst of sap.
- King Godzilla boasts supreme levels of regeneration, being able to regrow conscious Ghidorah heads in just a few minutes between losing them. The only part of his body which doesn't regenerate is his chest, which instead alters itself and grows the Biollante Head.
- King Godzilla can use the necks of his Ghidorah hands to strangle or ensnare opponents.
- King Godzilla is the fourth and final member of a tetrad of monsters created specifically by Kodansya for the manga, with the others being Sea Baragon, Flying Ebirah and Machine G.