Greninja

“	It appears and vanishes with a ninja's grace. It toys with its enemies using swift movements, while slicing them with throwing stars of sharpest water.	„
	~ Greninja's Y and Alpha Sapphire Pokédex Entry

Greninja the Ninja Pokémon, is dual Water-Dark type Starter Pokémon from the Kalos Region. The evolved form of Frogadier, and the final evolution of Froakie.

Video Games

Pokémon

Greninja has only appeared in one Pokémon generation, the sixth one. It cannot be caught in the wild, making it obligatory to evolve Frogadier or trade. Despite being native to Kalos, it can still be transfered to some games in later generations.

In the competitive scene, Greninja is top tier thanks to its speed and its Hidden Ability Protean, which makes it change its own type to the attack it is using, giving its attacking moves a boost.

Pokémon UNITE

Being one of the first Pokemon in the roster, Greninja sports the attacker class. It is has a unique basic attack; performing different attack depending on how far its target is.

Starting off as a froakie, it evolves into Frogedier at level 5, which it can then learn either Double Team or Smokescreen. At level 7 they evolve into Greninja, learning either Water Shuriken or Surf.

Super Smash Bros.

Super Smash Bros. for 3DS/Super Smash Bros. for Wii U

Greninja appeared as a newcomer playable character in Super Smash Bros. for 3DS/Super Smash Bros. for Wii U.

Super Smash Bros. Ultimate

Greninja appears as one of the many unlockable fighters in Super Smash Bros. Ultimate. It is speedy and can use Water Shuriken as well as fight up close.

Greninja transforms into Ash-Greninja when performing its final smash.

Greninja was fighting alongside lucario when Galeem attacked. Both tried to escape but were vaporized and imprisoned by Galeem. After Dharkon took over, Greninja must be beaten to join Kirby and the other fighters against Dharkon and Galeem.

Anime

Ash's Frogadier evolved into a Greninja in the episode A Festival of Decisions! and is able to change into a special form called Ash-Greninja, which is a result of the strong bond between it and Ash. While the form is well received, Ash-Greninja is the main reason why Ash did not obtain a Mega-Evolved Pokemon in the XY series as the writers made Ash catch Generation VI only Pokemon to promote the games. Greninja was also created in response to the two universally hated overused concepts: non-fully evolved main protagonist Water starters (Ash's Squirtle, Ash's Totodile, Brock's Marshtomp, May's Wartortle, Dawn's Piplup and Ash's Oshawott) and non-fully evolved Water-types Ash has (Squirtle, Totodile, Corphish, Buizel, Oshawott and Palpitoad).

Ash released his Greninja so that it can protect Kalos from the roots of the remaining Giant Rock with help from Squishy and Z-2, the two Zygarde, symbolizing someday that Ash's Greninja will rejoin Ash in the future after all of the remaining roots of the giant rock are all destroyed. The release episode, "Facing the Needs of the Many!" is universally hated by fans due to how forced the release was, as well as bringing back the roots despite most of them being destroyed during the Team Flare arc.

In Pokémon Journeys episode 108: Catching the Aura of Fate!, Ash’s Greninja returned in Journeys after a long absence and reunites with Ash. Ash’s Greninja teaches Ash and his Mega Lucario new moves and how to boost up its aura powers. While episode 108 is well received by fans, some are disappointed that Ash’s Greninja didn't officially rejoined Ash's team.

Sanpei also owns a Greninja.

Ash-Greninja battled against Alain's Mega Charizard X in the finals of the Kalos League; but was defeated; resulting Ash losing the Kalos finals. This was; due to Mega Charizard X being part Dragon; making it Water-resistant, as well as the fact that; Alain had more practice; with Mega Charizard X compared to Ash-Greninja, therefore; if the circumstances were completely different; Ash-Greninja obviously would have defeated Mega Charizard X and winning the Kalos finals.