Welcome Poke-fans. Since this is one (if not THE most) popular fanfic type out there, I decided to try my own. This is my first Pokemon fic ever, so it's probably not gonna be that great. Let me start by explaining whats going on:
1) This story will explore a "What If" scenario, if Greninja stayed with Ash (yes, I know this has been done once before, but hear me out!). Personally, I was a little pissed the anime let him go, the writers seem to do that a LOT when Ash gets a powerhouse other than Charizard (ironically, Greninja is a contrast to him if you really think about it), but I understand cause that's just the way Ash is as a character. But still, the negative-energy-in-the-plants thing was just a BS way to take him off the show... my opinion.
2) Similar to above, I was upset they let Serena go. I honestly thought she was gonna be a Misty... ya know, follow Ash around for another season or 2 THEN try to be a Pokemon Performer. Then again, I'm not totally surprised. That aside, she is gonna go with Ash to Alola as well, so you can think of this as an Ash x Serena story with some Greninja x Braixen. Pokemon reflect their trainers feelings, right? :P
3) Despite my feelings on it, I'm gonna use the negative-energy-that-Greninja-can-see-in-the-plants thing for a plot device. I don't wanna reveal what's its for, but it has something to do with the... "events" that happen in Alola.
4) Ash, as well as his friends and classmates, will be at the minimum age of 14 in this story. Now that doesn't mean I have a problem with his "immortally" in the anime, but since the show had 3 Xmas specials and Pikachu's Anniversary, I'm fast-forwarding time here. Trying to be realistic... well, as realistic as you can be in fantasy ;)
5) This takes place after Ash got home from Kalos. Likewise, Serena will be in Alola (since she has a cameo appearance in the Sun&Moon games... you know what I'm talking about) because during the time-gap, she got upset and quit. Plaermo understands her feelings, by remarking she felt a connection between Serena and "that boy". However, her showcase was scheduled in Alola and the flight was already paid for, so basically Serena gets a free trip!
6) While at the airport, Ash in his excitement runs into Serena not realizing its her at first. Until he reaches for a certain hat that fell of her person. They of course had a staring contest and then a hugging moment, with Serena sinking into it and not caring if anyone saw. They had to explain to Delia and Oak (who Delia ran into cause he was visiting his cousin in Alola) who she was, with Delia embarrassing Ash by saying "oh, so your the pretty girl he keeps talking about."
7) I won't be following anime exactly, I will be mixing the games storylines' with it.
Other than that, I'm aiming to make a plausible plot as to what could have happened if Greninja was allowed to stay in the roster. Also unlike my other stories (if your a reader of them), this one won't be given much attention unless I get a decent amount of reviews/follows/favs. Any reviews: good, bad, suggestions, criticism, etc. If this story is bad, say something! I'm a big boy, I can take it!
Oh, and before I forget; Pokemon belongs to the Pokemon Company, meaning I don't own it or any of its source material. That includes any songs I may use from the franchise and I'm merely using lyrics [if I write them] for dramatic effect. Since I'm also not getting paid for doing this, I'm not breaking any laws, this is just a hobby that I do in my spare time.
Narrator:
When we last saw our heroes, they had tearful good-byes to pursue their own dreams. Among them, was the highly unexpected departure of Greninja, whom stayed in Kalos to help the 2 Zygrade; Squishy and Z2. Some of the corrupted energy from Lysandre's plan infected the wildlife, causing roots to spiral out of control. Neither Zygarde could easily track down the inflected land, but Greninja's mysterious powers were able to locate them instantaneously. It wasn't easy, but Ash did the honorable thing and released Greninja under the care of Zygrade, while giving each other a tender hug farewell.
Ash has had bonds with his Pokemon before, but none that manifested itself quite like Greninja's did. So much so that even after returning home, he was depressed for a week afterward. He didn't sleep or eat... heck, he didn't even battle Gary who challenged him with a new Pokemon he obtained recently! Gary, Professor Oak, Tracy, Mimey and Delia asked if anything was wrong and while Ash claimed he was fine... Pikachu knew the truth. Even Charizard was sensing something amiss with its trainer, but kept to himself about it. Ash did get over it after hearing they won a free trip to overseas... to Alola! He's heard of the location all his life and always wanted to venture there... especially cause of all the Pokemon he could meet and new friends he could make.
And so... enjoying a relaxing vacation from all the world-saving and badge-collecting; Ash, his mother, Professor Oak and even Serena whom Ash happened to bump into at the airport; could do with some sunshine and spending quality time together. But what of Greninja? How is he adapting to his new lifestyle in the past month? Well, why don't we just drop in, and find out!
-SONG START- (AN: You know, THAT song! I do not own it, just modified it to fit the mood and setting)
(Koko Tapu flies around in the sky. An unidentified Pokemon appears from a hole of some kind as Koko Tapu exits off-screen.)
I still wanna be, the very best! The best that no one ever was.
(Ash looks up to the sun, it shows he's looking up at some kind of league.)
To catch'em all, is my real test! And to train them is my cause!
(Ash catches a Pokemon and gets excited. Pikachu joins Ash in a pose... so does Charizard, who gives him a "kiss".)
I've traveled, across the land! Been searching far and wide!
(Ash runs with Pikachu and his classmates. Some Pokemon fly around them, which gets Lillie nervous and hugs Ash for protection. Everyone sweatdrops... except a certain french girl, who gets red and grows a forehead vein.)
Teaching Pokemon, to understand, the power that's insiiiiiiiiiiiide!
(Ash and Greninja fight a Tyranitar, with water exploding from Greninja's body, causing his well-known transformation.)
POKEMON! GOTTA CATCH'EM ALL!
Its still you and me... because its our destiny!
(Ash and Pikachu hug one another. The scene then changes to a battle, with said rodent avoiding an attack and executing Iron Tail on his opponent.)
POKEMON!
Yeaaaaaah! Your my best friend, in a world we must defeeeeeeeeeend!
(Ash and friends cheer Pikachu on, but then the sky opens up... what are those things flying out?!)
POKEMON! GOTTA CATCH'EM ALL!
Our hearts are true! Our courage will see us through!
(A few creatures of some kind interrupts the battle and attacks Pikachu, who dodges their assaults then responds with his signature move: Thunderbolt. One of the creatures go to attack Pikachu, but the unidentified Pokemon from before flies in front of Pikachu protectively.)
You'll teach me, and I'll teach you! PO-KE-MON!
(Lillie tries to confront her fear by petting Greninja, but reels back a few times until she finally touches him, realizing this isn't so bad. Her phobia finally conquered, she gives Greninja a hug, which he returns. Everyone else crowds around them, making a group hug.)
GOTTA CATCH'EM ALL! (GOTTA CATCH'EM ALL!)
(Ash throws a Poke-Ball, releasing the very same unknown Pokemon that protected Pikachu. It gives a battle cry, ready to fight!)
POKEMON!
-SONG END-
Ash: (instrumental music plays in the background) A Friend from Afar!
In the Kalos region, we see a Greninja leap out from some trees into an open field. He looks around, as if sensing something... that's when a giant root erupted from behind him! Using Cut, he sliced the destructive plant. More roots flew at him, so he spun around, slicing them as well. An even bigger root headed for him from in front, that's when Squishy (10% Forme) used Extreme Speed to ram into it. Another root erupted, this one was bigger than the rest. Z2 (50% Forme) arrived on the scene and disintegrated it using Dragon Pulse.
The 3 warriors then were back-to-back, waiting if anymore roots would pop up. Sensing no more negativity in this area, Greninja gave an "all-clear", so the trio could relax. Finding a safe enough spot in the shade, Squishy released its cells and changed back to normal, apparently he gets tired much easier than Z2 does. The red Zygarde core hopped on a rock that had a beam of sunlight, and laid down. Greninja just leaned against a tree, had his arms folded, looking up at the sky.
This wasn't the first time Greninja did this, ever since his trainer left him under their care, both Zygarde noticed the frog-like ninjas behavior. "Poor Greninja, he truly misses Ash" said Squishy. "He was called the Chosen One by Lugia years ago, it only makes sense" said Z2. Squishy was deep in thought upon hearing this, as a Legendary himself, he knew of Ash's status. "I think we should let him go" said Squishy. "Your not serious, are you? Greninja is our best chance at..." Z2 tried to argue, but Squishy met the blue-cored Zygardes gaze.
"He's done more than enough, we've traversed the entire Kalos region the past few weeks, and there's barely any negative energy left! Greninja has kept his end of the bargin and besides, its our duty as a Legendary, not his" said Squishy adamantly. Greninja overheard the conversation and while his heart skipped a beat, he still couldn't find it in himself to just abandon his home. He told this to both Dragon/Ground-Types, but they (in Z2' case, reluctantly) assured they could handle it.
It was time for Greninja... to return home.
-BREAK-
Alola Region - Melemele Island, Hau'oli City
Ash was laying down under an umbrella on a beach chair with Pikachu curled up next to him. It wasn't just them however; Serena, Delia, Oak and Mimey were doing the same thing. The funny thing was, Ash and Serena got their own while the adults and Mimey had to share. "So, the twerpette and The Twerp are an item now?" Asked a disguised Team Rocket member known as Jessie. The team were sitting on the ledge, watching the vacationing heroes. "First the redhead twerp, then Hoenn region twerpette, the blue-haired twerpette, the dragon twerp and now the french twerp... the boy's got his own personal harem" commented James. "Don't hate da game, hate da player" said Meowth. "WOBBUFFET!" Popped up Jessie's Wobbuffet, in which they dogpiled him, telling him: "shhhhhh!"
Serena had her Pokemon out for their Poke-Balls to enjoy the weather, commenting how she missed being with Ash, though she blushed immediately after saying that. Ash was staring out into the waters when he felt... something. He couldn't figure out what he sensed, but it felt... familiar somehow. He looked behind him and saw a blacked out Pokemon leaning against the building in the back. It must've noticed Ash staring or it decided to leave, either way it rushed across the street. Ash couldn't help be feel curious about this, and got up from his chair to follow the unknown figure. "Ash? Ash, where're you going?" Asked Serena, getting up and following her crush.
Pikachu, hearing the commotion, stretched and rubbed the sleep out of his eyes while yawning. He was stretching, and that's when he realized Ash wasn't here anymore. Where did his beloved raven-haired and unpredictable trainer run off to now? It still made him wonder how the heck he was able to get his 1st Pokemon, yours truly. He was about to jump down, when he was bagged... literally!
-BREAK-
Following the shadowy figure, Ash ran after it with Serena calling out to him, but he was too focused on the runaway Pokemon to notice. People assumed: "Aw, the cute couples chasing each other"... if Serena's face wasn't red from running or the sun, its definitely red now! Ash swore he felt this before, but couldn't place it. It felt so familiar and yet, he had no clue why he was doing this. For starters, its not like it was the Ho-Oh back from day 1, the shape and size was much different. Then again, the Pokemon running away moved like it was teleporting, so he could be wrong.
Leaping over a hole in the wall (AN: the hole where you take your 1st Poke-Finder shot), the Pokemon disappeared from sight. Ash jumped and pulled himself over the wall while Serena was running after Ash. Since she didn't share his Mankey/Primeape climbing skills, she asked a local male pedestrian if there was a way back there, which fortunately there was. Bowing and saying thank you, Serena ran off, with the man wishing her luck in finding her boyfriend... she had another red face going after Ash now. Back with Ash, having found the Pokemon running away, he could only stare... was this real? Was he ACTUALLY seeing this, or was he still daydreaming back on the beach?... OW! That self-pinch hurt! "Ash! What's wrong, why did you...?" Serena asked him, but she too could only stare...
...
...
...
It was a Greninja.
-BREAK-
Back at the beach, chaos erupted as 2 men in dark clothing robbed Pokemon right in front of trainers' eyes! Luckily, Professor Oak and Delia were able to hide with an illusion Mimey created of an empty spot on the beach. (AN: According to Pokedex entries in the games and books, Mr. Mime's illusions can become real if his/her opponent believes they are.) But when Pikachu was grabbed, Serena's Pokemon just couldn't tolerate sitting around and leave a friend in need. Pancham was the first to jump out, using Dark Pulse towards the thugs. However, a Magneton blocked the attack with its body(s) and a Golbat swooped in and used Wing Attack on the poor panda-like Pokemon.
Braixen unleashed a Fire Blast on the opposing Pokemon, but a third one nullified the attack, this time it was a Pokemon none of them had seen before. It appeared to be a Rock-Type jackal, meaning Braixen's attack was almost useless. The jackal-like beast used Crush Claw and attempted to attack the stick-wielding fox, but Sylveon managed to block the attack just in time with Protect. The jackal gave the Fairy-Type an evil dirty look, making her tense up, and then the jackal onslaught the Fairy Eeveelution's shield with Outrage. Not expecting a move as brutal as that, Sylveon's shield was destroyed and she was knocked back.
Of course, being a Fairy-Type means she was immune to the Dragon-Type damage, but not the super effective Magnet Bomb that originated from Magneton. With 2 of its allies beaten so easily, Braixen began to cower. Then, a memory of a certain frog flooded her memory and what he would do in a situation like this. The Fire-Type released a hellfire of Hidden Power, striking each opponent and while they weren't knocked down, they did struggle to get up.
A flash from a Poke-Ball was heard behind Serena's starter, it was a large customer too. All it took to bring the fox down was a swipe of its claws, a 3rd thug was revealed to be its trainer. "Feisty one, aren't ya? Heheheheh..."
-BREAK-
The Kanto and Kalos natives could not believe their eyes. A Greninja, here of all places! Although Serena didn't know of Ash's depression back in Pallet Town, she had a taste of it with Braixen for a reason she couldn't figure out. The french teen wrapped her arms around Ash's left. "Come on Ash, we should..." she wanted to say, but something rustled in a bush behind the ninja-like amphibian. "It's been awhile, hasn't it?" Said a green... thing with a red core. "You humans are your emotions are so confusing" said a voice, originating behind a tree. It was revealed to be a now-visible Zygarde!
"Hey, aren't you both from Kalos?" Asked Serena. "Wait... then that means..." said Ash, his eyes widening in realization. That's when the Greninja brought out its left arm... it had a device around it!