The 100th episode of the Pokemon Journeys featured a new opening title sequence that teased a number of upcoming plot points and Pokemon that will be appearing during what is presumed to be the final stretch of the series. Among the Pokemon that appear in this new intro is Ash’s Greninja, a fan favorite Pokemon who hasn’t been seen in the anime in almost six years. We only get a brief glimpse at Greninja so it’s impossible to say what role it will play, but just knowing Ash’s Greninja will return is reason enough to be excited.

Greninja was the first Pokemon that Ash caught when he arrived in the Kalos region. Froakie sees Ash and Team Rocket fighting and jumps in between Wobbuffet and Pikachu to protect Pikachu from an attack. Ash rushes the injured Froakie to Professor Sycamore’s lab and learns that it has been abandoned by its trainer for being uncooperative. It turns out the Froakie has had multiple trainers but could never get along with any of them. After another row with Team Rocket, Froakie decides to let Ash be its new trainer, and the two were inseparable for the next 138 episodes.

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Like most of Ash’s Pokemon, Froakie took some time to find its true power. It took a few bad beats early on from Penelope’s Sylveon, Sanpei’s Frogadier, and Ash’s Hawlucha, who later became its closest friend. It lost against Grant’s Tyrunt at the Cyllage Gym, but in a rematch against Sanpei, finally evolved into Frogadier.

From there, Frogadier became one of Ash’s most prolific fighters. It practically single-handedly won Ash the Plant Badge at the Courmarine Gym, it defeated Sawyer’s Treecko even as it evolved into Grovyle mid-battle, and it took out Olympia’s Meowstic, earning Ash Anistar Gym’s Psychic Badge.

Ash Commanding His Greninja In A Pokemon Battle

Frogadier was basically undefeated until Ash and his friends came up against the Ninja Army in A Festival Of Decisions. Ash’s team was defeated by Heidayu’s Bisharp, but during a rematch, Frogadier threw itself in front of an attack to protect Pikachu again and evolved into Greninja. Moments later, it seemingly evolved again into a new, unknown form that had a color scheme matching Ash’s outfit. This temporary form came to be known as Ash-Greninja and is still the most unique phenomenon in Pokemon history to this day.

Ash-Greninja is a Bond Phenomenon, or Battle Bond as it's known in the games. When trust between Ash and Greninja is at its highest point, Greninja is able to temporarily evolve into Ash-Greninja. While in this form, Ash is able to see from Greninja’s perspective and can feel Greninja’s pain when it gets hit with attacks. Greninja also gets a boost in power while the bond is active.

This is a bizarre phenomenon that has never been discovered in any other Pokemon. It’s not just that it’s exclusive to Greninja - it’s exclusive to this Greninja. As far as we know, Ash’s Greninja is the only Pokemon that has ever existed that has the power to Battle Bond.

As you might expect, Greninja only became more special to Ash - and more powerful - as the X & Y series went on. Ash uses Ash-Greninja to win battle after battle throughout the Kalos region, only ever losing when the pair pushed this power too far, causing them to pass out from exhaustion. They eventually perfected the form and used it to reach the Lumiose Conference finals and take on Lysandre’s Zygarde-like Giant Rock, the final antagonist of the X & Y series. Unfortunately, parts of the Giant Rock survived, so Greninja ended up leaving Ash to help the real Zygarde find and destroy them. We haven’t seen Ash’s Greninja since then, but it's presumed he’s still in Kalos with the Zygarde pair, Squishy and Z2.

Because of its unique characteristics, Ash-Greninja is the most recognizable individual Pokemon of all time. It has appeared in Sun & Moon’s special demo as a transferable Pokemon and even has its own Black Star promo card in the Pokemon TCG. Its return to the anime is highly anticipated and the reunion between Greninja and Ash will undoubtedly be a huge moment for the legacy of the anime. Even if we never learn more about the Bond phenomenon, it will be great to see Ash-Greninja join Ash’s team once again.

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