It is not known to evolve into or from any other Pokémon.
Along with Entei and Suicune, it is one of the legendary beasts created by Ho-Oh after the burning of the Brass Tower. Of the three legendary beasts, Raikou is said to represent the lightning strike which ignited the fire that consumed the Brass Tower.
Raikou is a yellow tiger-like creature with black stripes that resemble lightning bolts and a white under-side. Raikou has a skinny, light-blue tail with an electric spark-shaped formation at the end. Raikou appears to have a grayish-purple cape that is supposedly made of thunderclouds. Most of Raikou's face is white with a light-blue "X" on its face and a gray crest on its forehead. Raikou has red eyes and long fangs in its upper jaws that make its appearance similar to the sabre-tooth cat.
Gender differences
Raikou is a genderless species.
Special abilities
Raikou has the ability to shoot bolts of lightning from the rain clouds on its back. Raikou can also attack using its fangs and has limited psychic powers. Raikou has also shown an ability to create storm clouds from its cape, allowing it to fly, however this ability has only been seen in the Pokémon Adventures manga, whilst attacking Falkner, and in a Pokémon Ranger: Guardian Signs special.
Behavior
Raikou is normally distrustful of humans due to the fact that humans have tried to capture the Legendary Beast of Thunder for many centuries, though it has shown some friendship with those that just wish to help it. Raikou tends to show up either when there is a thunderstorm or when other Electric-type Pokémon are in danger.
Raikou was awakened by Yellow along with its two counterparts, and the three raced around Kanto and Johto looking for Trainers to help them defeat the Masked Man to free Ho-Oh and repay the debt of the latter for saving its life. Nearing the end of the chapter, Raikou eventually pairs up with Lt. Surge after encountering and escaping Falkner, and later Gold. Once Ho-Oh is freed and Pryce, the true identity of the Masked Man, is defeated, it once again roams the lands of Johto with Suicune and Entei.
Anabel also owns a Raikou in the Battle Frontier saga. It has been confirmed that it is the same Raikou as the one that befriended Gold, having caught it sometime before the Emerald arc in Johto. Raikou is more powerful than any other Electric-type Pokémon in the manga because billowing thunder clouds follow it everywhere carried on its back, allowing it to perform powerful attacks, such as Thunder, more quickly and efficiently than regular Electric Pokémon. Despite clearly possessing sentient intelligence like its fellow beasts, it obeyed Anabel's commands to battle Emerald without question while she was under psychic control of Guile Hideout. After he is defeated and the Battle Frontier is saved, Raikou is seen interacting with Gold and Crystal, and has not appeared since.
When released from a Poké Ball, Raikou releases a powerful Spark attack that electrocutes any opponents that get caught in it. Raikou is the only legendary beast that does not return in Super Smash Bros. Brawl.
Trophy Information
Raikou also appears in Melee as a trophy.
These Thunder Pokémon travel near and far, blasting out electrified whirlwinds. They carry storm clouds on their backs, so they can produce lightning regardless of the local weather; it's even said that they descended to the earth with via lightning bolts. Their extreme quickness lends itself to flight, so they're very hard to capture.
Game data
Pokédex entries
This Pokémon was unavailable prior to Generation II.
Raikou embodies the speed of lightning. The roars of this Pokémon send shock waves shuddering through the air and shake the ground as if lightning bolts had come crashing down.
Raikou is the only Pokémon in the anime whose image on the anime Pokédex was of stylized art rather than Ken Sugimori's official artwork for it.
Raikou is the only member of its trio not to be weak to another member of its trio. Entei is weak against Suicune and Suicune is weak against Raikou, but Raikou is not weak to either of them.
The order that the beasts appears in the National Pokédex is the order of the events that happened at the Burned Tower; the lightning that started the fire (Raikou), the fire that consumed the Brass Tower (Entei) and the rain that quenched the fire (Suicune).
Raikou is particularly based on the Thunder and Lightning gods of most cultures surrounding the world, mostly the 雷獣 raijū, a thunder demon of Japanese lore. It is said to be a creature that could take the form of a tiger, monkey, blue wolf wrapped in lightning, and many other animals. Raikou is specifically based on its tiger form, while the Pokémon Manectric is based on its wolf form. In terms of physical build, Raikou is based on the Smilodon fatalis, a well-known but extinct species of wildcat often referred to as a saber-toothed tiger. Its color and pattern scheme are reminiscent of that of a Bengal Tiger. The stripes that decorate Raikou's body also can be compared to zigzagging thunderbolts and perhaps even scars from claws. The white ruff around Raikou's face is akin to the Siberian Tiger's thick fur around its neck. In the anime, Raikou is shown to be very agile, swift, stealthy, and a powerful attacker, just like a tiger. The gray "plate" atop its head may be similar to Entei's head ornament, being either a helmet or crown that signifies courage and power.
The flowing purple mane on its back is likely meant to invoke the image of a cumulonimbus cloud, the cloud type most often associated with thunderstorms.
Name origin
Raikou could be taken to mean 雷光 raikou (lightning), which is also the inspiration for the name of raijū, or it may be a combination of 雷 rai (thunder) and 皇 kō (emperor). It may also derive from 雷公 raikō (thunder duke), identical to the name of the Taoist deity Lei Gong.