Rayquaza

Rayquaza is a large, green, serpentine Pokémon that also resembles a missile. It has red-tipped, rudder-like wings on its shoulders and down its body, and similarly patterned fins on the tip of its tail. Yellow ring-like symbols run across the length of Rayquaza's body and it has an additional yellow ring on top of its head. Rayquaza has two limbs with three-clawed hands, and two long, flat, horn-like structures on its head, with two shorter horns along its jawline. It has small, yellow eyes with black pupils, prominent pink gums, and two discernible fangs in its upper jaw.

Rayquaza has a strong and endless desire to do heroic deeds for the Pokémon world. Rayquaza is said to be equal to both and Kyogre. For that reason, it is the only one who can halt the endless battles of the other two super-ancient Pokémon, by overpowering them and forcing both back into their slumber, even in their Primal Forms. Rayquaza is also the only one who can stop the two and restore order to nature that they disrupted. Rayquaza is said to have lived for hundreds of millions of years in the ozone layer, where it feeds on water and other particles. There, it feeds on meteoroids, which includes Mega Stones and even Minior. It also loves Rayquaza Treats made by Snacksworth, who once encountered it in the past. Rayquaza is rarely seen by people; even in flight, its appearance is indistinguishable from that of a meteor. For living in the ozone layer, it can breathe in outer space.

Rayquaza possesses some of the strongest attack power out of any Pokémon; it can easily summon cyclones to overwhelm its opponents. It can soar into the sky and drop out into its foes at high speeds, causing huge damage. Thanks to its weather-manipulation powers, it can eliminate weather effects. Rayquaza was worshiped by the Draconid people as the savior of the region since ancient times. Thus, they built the Sky Pillar to honor it. Additionally, it can be summoned atop Sky Pillar by multiple Key Stones. In Pokémon Adventures, the Draconids referred to it as their "Dragon Lord". It is one of the longest-lived Pokémon species. Inside its body lies an organ that contains the same power as a Mega Stone, which was named the "mikado organ" (Japanese: ミカド器官) by a Devon Corporation scientist.

Rayquaza is bitter enemies with , an extraterrestrial Pokémon that repeatedly invades its territory, with the two often clashing with each other in space. This is depicted in the movie Destiny Deoxys (M07) and in the games Omega Ruby, Alpha Sapphire, and Masters EX.