King Ghidorah, sometimes spelled Ghidrah or Ghidora or even Ghidra, is a daikaiju featured in several of Toho Studios' Godzilla films and (in derivative forms) in their Mothra Trilogy. Ghidorah is among the most powerful creatures in daikaiju eiga with a reputation that has earned him the title "The King of Terror". Ghidorah is a golden dragon-like space monster with two legs, three heads on long necks, bat-like wings, and two tails. It was said to be 100 meters tall with a 150-meter wingspan and to weigh 30,000 metric tons.

Gojira's appearance has changed over the years, but many of his characteristics have remained constant. One characteristic that has remained stable is his roar. It was first created by Japanese composer Akira Ifukube by rubbing a resin glove over the strings of a contrabass. Other characteristics that have remained constant across all the Japanese films have been: Gojira being depicted as a gigantic dinosaur with rough, bumpy charcoal grey scales, a long powerful tail, and jagged, bone colored dorsal plates. Although his origins vary somewhat from film to film, he is always described as a prehistoric creature, who first appeared and attacked Japan at the beginning of the Atomic Age. In particular, mutation due to atomic radiation is presented as an explanation for his great size and strange powers.

In the Showa era films, Gamera was a gigantic, prehistoric species of tortoise, reawakened by an accidental atomic blast in the Arctic during a dogfight between US and Russian fighters. The film mentioned that Gamera had appeared before, from pictographs depicting Gamera, and warning of his ability of flight. Gamera's origin was given that he was a leftover from eons in the past. Gamera was already capable of flight and breathed true flames, rather than radioactive energy when he was reawakened. And while it was known that he fed on flames, the explanation for this power is that the age in which he lived lacked oxygen but was volcanically active thus causing Gamera to feed on fire.

Gigan's forelimbs sport a pair of large metal hooks in place of hands. Gigan can use these to batter an opponent and to stab. Gigan has a pair of retractable wings which is capable of allowing it to fly at speeds of up to Mach 3. This normally assists in interstellar travel and is utilized very little, if at all, during battle situations. When it is used in battle, however, Gigan will often use it to engage in aerial slams to continuously topple his opponents without giving them a chance to counter, or even get up.

Appearance-wise, Angilas is a four-legged dinosaur that looks similar to an Ankylosaurus. He has several horns at the top of his head and a single horn above his nose like a rhinoceros. His face is long and drawn out, like a crocodile, and has rows of jagged, serrated teeth. His carapace is studded with long, sharp spikes. Angilas' tail is covered with spikes and makes up most of his body length. His hind limbs are longer than his forelimbs and he can stand up on them to his full height, though he generally walks upon all fours.

In the Showa series, Baragon was a giant therispid, who burrowed underground to escape extinction and survived while all other prehistoric creatures like him died. He adapted to the environment and lived successfully. Baragon is a four-legged reptile with a horn on his head and large ears. His main weapon is a heat ray that he can fire from his mouth. In addition, he can jump very high and burrow through the ground. Baragon is not to be confused with the Gamera series kaiju, Barugon, despite some similarities between the two creatures.

Rodan's primary weapons are his speed and agility; he can create hurricane-force winds in his wake by flying at supersonic speeds at low altitude. He also uses his beak and talons effectively in battle, the former being depicted as sharp enough to smash through rocks, and his wings, despite their delicate appearance, are quite durable. Rodan possesses great physical strength, able to lift and carry monsters heavier than himself. Rodan developed the ability to emit a radioactive heat beam from his mouth, after exposure to Godzilla and a radioactive waste disposal site. He can also make very strong supersonic waves to make the air pressure cause buildings to explode and turn into flames.