Gyaos

Gyaos (ギャオス Gyaosu) is a winged kaiju that first appeared in the 1967 Gamera film, Gamera vs. Gyaos. Gyaos is considered to be Gamera's arch-enemy, and has more film appearances than any of his other enemies.

Origins
Gyaos has no definitively explained origin, and is discovered living in a large cave. It is revealed that there are multiple silver space-faring Gyaos, suggesting that Gyaos may be an extraterrestrial species, or that there are multiple species of Gyaos specific to other planets.

History
Gyaos appeared in Japan from a large cavern, and feasted on blood, principally that of livestock and humans. Soon, Gamera confronted Gyaos, and after a battle Gyaos fled while Gamera slept in the ocean to recover. It was soon learned that light caused Gyaos' skin to shrink, so the light of the city stadium of Nagoya kept Gyaos at bay. Gamera soon returned to finish Gyaos off and, after a battle in the air, Gyaos cut off its own foot to escape from the sun. Humanity developed a plan to place artificial blood on a rooftop in Nagoya to keep Gyaos drinking the blood for so long that the sun would come up and kill it. But Gyaos proved more cunning than originally thought and used a strange fog attack to protect itself from the sun. The next plan was to lure Gamera to Gyaos' lair in the forest by setting the forest alight. Gyaos used its fog attack to put out the flames, but Gamera arrived and eventually defeated Gyaos by throwing the beast into a volcano.