A/N: Written for the Diversity Writing Challenge, f59 – write a fic with scenes longer than 150 words.

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amphibian.

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1.

He'd always been a strong swimmer, but now it seemed he could dive even deeper. Although…there was never really a reason for him to need to. There were oxygen tanks and special suits, and for the higher pressures the submarine, and he wasn't an ocean explorer anyway. He swam recreationally for the most part…unless he was on the occasional rescue mission. Like plucking certain healing plants from the lake. Or, more often, catching a wayward human or pokemon about to be swept off the edge.

So he didn't notice it for a while. Not until they were horsing around and Bonnie and Chespin were trying to see who could hold their breath the longest. And so they all joined in. And he was comfortably swimming behind Greninja until the amphibian pokemon surfaces and beckoned to him.

And he surfaced as well, hair clinging to his skull and eyes watering a little as he stared at the worried faces of his friends.

The next time they went swimming, Serena had to dive in again after him. Even though he was fine.

And he remembered that time when he'd been underwater too long, when he'd been hanging onto Lugia's neck for both their lives and they'd been sinking, slowly sinking into the abyss with Lugia's wings trapped by that hunter's rings… Misty had swam after him then. Misty had pulled his unconscious, floating, body out of the waves and dragged him to shore, and Tracey had called to him until he woke, coughing seawater. And he hadn't been five minutes ten.

They'd waited exactly five before Serena dived after him again. A normal human wasn't supposed to be able to stay underwater for more than three.

Ash just shrugged. He had no idea what was going on. Greninja shrugged as well.

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2.

Ash had been in plenty of pokemon battles, but somehow, battles with Greninja were different. Battles with Pikachu were different too but the difference there was obvious: Pikachu was his first pokemon and, by this point in time, they basically shared a wavelength. Pikachu knew him the best out of all their pokemon, and he knew Pikachu the best. It was a fact the rest of his pokemon understood, and simply had to accept. They had their problems occasionally, like Chikorita. They had their saving graces, like Froakie. But in the end they were all Ash's pokemon, and they knew Pikachu was the first.

And yet there was something else about Greninja. Yes, he grew passionate with every battle, with every pokemon, and even more so when they were down to the wire. But this is different. And it's not the torrent ability either. He's not sure if he's ever even seen a pokemon activate that ability, but he's seen both blaze and overgrow and it's different. Infernape and Sceptile. It's different. They don't affect him the same way. They don't make him dizzy in the heat of battle, and exhausted and sore in the aftermath as though he was dashing at speeds impossible for the human body, attacking when all he had was his fragile little hands…

It was almost as though he was pulling off that final victory move with Greninja, but he was still standing on the sidelines by the end of it so that was impossible.

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3.

His aches and pains went away quickly. That was always nice, and he'd always been quick to heal but these were different aches and pains and they went away the fastest of all. They were the aches and pains of a battle he'd stood on the sidelines and barked orders for. And Greninja was quick to recover as well. Even when they lost that battle against Alain. Nurse Joy had looked at the poke ball with a baffled expression on her face. 'Your Greninja's fine,' she said. 'Are you sure you used him in a battle?'

'Of course I'm sure,' Ash replied.

'We all saw it,' Clemont agreed.

'And poor Greninja lost,' added Bonnie.

She shrugged. 'Well, Greninja's in perfect condition. Though you look a little peaky.'

Ash was a little tired at the time, but it wasn't anything a little break couldn't cure.

And when he faced Malva later on, he didn't even need that to be back on his feet, and neither did Greninja.

Her Houndoom did need the rest, though. That was their advantage: that speedy recovery their opponent proved unable to match.

He wasn't sure if that counted as a victory against a member of the Elite Four or not, though.

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4.

The fast gym battle he'd ever fought was against Wattson at the Mauville Gym, but they had the excuse of Pikachu getting super-charged by the electric Raikou. And they'd cleaned swept it as a consequence. One move per battle. Pikachu all the way. He didn't think he'd ever top that.

He didn't. But he equalled it against the Snowbelle Gym.

It wasn't overconfidence. He still didn't count that victory against Malva. He wasn't sure what the others thought of it. They seemed in two minds. Ecstatic he'd taken another leap towards his dream. Cautioning him not to get too overconfident and letting his battling abilities suffer.

He almost feels bad when Avalugg, the last of the three, crumbles into defeat. But he feels jubilant as well. There's his entry into the Kalos league. There's his dream.

And there's Greninja, as powerful as ever: the wisdom of a thousand battles, or more, behind his eyes.

He still doesn't understand, back then. Neither does Wulfric, who surrenders his badge with astonishment still clinging to his face like fluffs of snow. 'Only ever seen one trainer plow through my gym like that. Guy with a mega Charizard.'

Somehow, he knew Wulfric was talking about Alain. Greninja knew that too.

'You want to settle the score, don't you?'

He wondered if they could beat mega Charizard now.

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5.

They got their chance to test that theory. Alain stood between them and the world. On the side of the enemy and the both of them are saddened to see him there because he'd been nice and a strong battler as well, and it was always a shame when people like that wasted away on the wrong side.

So they'd just have to douse those hell fires and bring him back, right?

They battled.

This time, both pokemon were at full strength. Like the last time they'd fought. Not like when they'd fought against Malva and her Houndoom the second time. She was there. She was glaring. She wanted her revenge but she wasn't going to step on Alain to get it.

That was fine. They'd battle her once they were done. They'd prove their strength, their bond, the reason Froakie had all that time ago chosen Ash to be his trainer…

Mega Charizard fell. Houndoom fell. After the pair of them came the leader of Team Flare himself. And then Pyroar fell.

And, finally, Ash and Greninja fell.

They still had limitations: individually, and together.

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5.

'I don't understand,' Nurse Joy was saying, when he awoke. 'The dehydration makes some degree of sense. But how does he have hypothermia when battling fire – oh.'

He'd surprised her, apparently. She dropped her clipboard and scrambled for it again. Pikachu jumped into his lap, and Dedenne too. And Serena, Bonnie and Clemont grinned at him, with varying degrees of bafflement.

'Sorry guys,' he said sheepishly. 'You're going to have to explain what happened.'

'We don't know ourselves,' confessed Clemont.

They knew a lot more than him, though.

Somehow, he'd gotten cold. While battling one fire pokemon against another. With Greninja. And dried out too. Like all the water in his body had been squeezed out. One water shuriken after another. But he hadn't been using those water shurikens. Greninja had.

He'd activated Torrent against Pyroar too, hadn't he? He remembered that. All the water in his body boiling – but not so painfully that it cooked him from the inside. Boiling like passion boiled. Like anger boiled. Like desperation boiled.

He'd seen Blaze before. And Overgrowth. But Torrent he understood the best, because of a bond that still escaped them all.

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6.

Pikachu's thunderbolt hurt more, now. It was because Pikachu was becoming stronger, he thought.

A part of him was starting to put it all together though.

Hawlucha's karate chops hurt more too.

It had nothing to do with Pikachu at all. It was Greninja. The water and dark type. Weaknesses to thunder and fighting type moves, amongst others. Greninja's weaknesses…as well as his strengths, becoming his own. And the other way as well.

He no longer had to call out attacks. No longer had to do more than simply come up with the idea and Greninja was executing them.

Sometimes, in those battles, he wondered where Ash stopped and Greninja began. Who was fighting. Who was watching from the sidelines. And why was this only Greninja? What about all his his other pokemon? Pikachu, who'd been with him the longest? Noivern, who'd been with him since his infancy? Talonflame, who'd also undergone two evolutions under his tutelage? What about all of them?

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7.

It affected Pikachu the worst. Because they were the closest. Best friends and partners for years, and yet they didn't have this connection.

Sometimes, he found Pikachu staring at that box that had once held a thunderstone.

He didn't ask if Pikachu had changed his mind. He didn't want Pikachu to have changed his mind.

But he tried not to battle so much with Greninja. He'd been neglecting the others, to an extent. He made up for it now. Battling with all of them, and Greninja last. Something was always missing until Greninja came out on stage.

It made Pikachu sad. Muddied his coat. Drooped his ears.

Ash and Greninja were two different beings, and only one was Pikachu's best friend. Only one of them had travelled with him for years. Only one of them had restored his faith in pokemon, and saved him time and time again. Only one of them had that special, tender place in his heart. And that was Ash. That was Ash.

But where did Ash stop and Greninja begin? He still hadn't worked that out.

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8.

They made it all the way to the top. Won the Kalos league. Finally, a step up. And it was him and Greninja in the final stretch. Where Pikachu had wanted to be. But Pikachu had gone first. Taken out two pokemon before he'd fallen. Paved the way. Pikachu hadn't minded doing that, once upon a time.

But circumstances had changed now.

The others didn't realise it. Or maybe they did and couldn't see a way to fix it, like he could not. They cheered for him. Congratulated him. Hugged him and he felt their hands slide of his skin like there was a sheet of slime or water in between. When he hugged Greninja before, it hadn't felt like that. They'd touched directly. Skin to skin.

Humans were becoming strangers. Even his friends.

Did things have to change like this for him to obtain his dream?

Then there was the Elite Four. Malva was first and she was full of spite but she couldn't stand up to Greninja. The others got a longer battle. Other pokemon first. Greninja last. He beat them all.

Then, finally, the time came to face Diantha once more.

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9.

He hadn't expected it to come to this. Pikachu verses Greninja. Not for a spot for who faced Diantha's Mega Gardevoir. For something else. Something that none of them really understood.

And, for the first time, he could hear Pikachu's voice, word for word.

'You can't keep monopolising Ash. He's my precious partner! Not yours!'

But Greninja didn't understand. He wasn't the jealous sort. Hadn't he always helped the rest of Ash's pokemon?

'But you…become Ash.'

But he couldn't help that.

'You change him!'

And that's the crux of it. Pikachu wanted the old Ash back. The Ash that was his partner: the Ash he'd travelled with for so many years.

But where was that Ash now? And how could he give him back…

'He won't be human anymore if you go on…'

And, in a sudden flash of clarity, that was a terrifying thought.

'Leave. You can save Ash that way.'

Greninja didn't want to leave. Didn't want to walk away from Ash.

But that sudden realisation, screamed out like that, shook them both.

Maybe…he really did have to leave.

No! He wouldn't!

He fired a water shuriken.

Pikachu repelled it with an electro ball.

'Leave!' he cried again, following with a thunderbolt.

Ash didn't want to fight against Pikachu. Greninja didn't want to fight against Pikachu either.

He let the thunderbolt hit.

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10.

When he woke up, Greninja was nowhere nearby but not gone. Not yet. He was waiting for him. Pikachu seemed to know that too. He was watching the window.

'Pikachu…' Ash began.

'I'm sorry,' Pikachu replied. 'But you're changing. I can't let you disappear forever.'

'I know.' He didn't want to disappear forever either. If it had been someone else, he'd have done that in a heartbeat.

But it was him. So Pikachu had to do it for him.

But the choice was still his. To free Greninja. To say goodbye to him as a battling partner forever. To say goodbye to those battles where he'd been there: attacking, flying, leaping into the sky…

He wasn't a pokemon, though. He was a human and humans simply couldn't do that.

'You do enough the way you are,' said Pikachu. 'You're doing too much now to be human.'

Humans couldn't survive five minutes without air. Humans couldn't get up while in complete exhaustion. Humans couldn't recover energy so fast – not even with an emergency dose of glucose and he hadn't even had that.

And humans didn't fight on the pokemon battlefield. They guided from the trainer's box. They helped off the field. They cheered from the sidelines. That was their role.

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11.

Greninja was speaking to him. Not pokemon speech. Human speech. The others gaped at the pair of them.

Ash ignored them. He only had ears for Greninja right then.

'I'm sorry,' he said. 'It was selfish of me to continue when I realised I was dragging you with me.'

Ash shook his head. 'I called you out. Again and again…'

'I wanted to come out.'

And that was the crux of it. Greninja wanted to battle for Ash. Just like his other pokemon. So why was this something only the two of them shared? They still didn't know.

'I'll ask that you free me.'

'Will you really leave?'

But they both knew the answer.

'I must. But I won't be far. Even if I am not your pokemon on record any more, I will follow closely, as your guardian and the guardian of your pokemon.'

And that was the best goodbye he could ask for, even though it would certainly sadden Greninja very much, in the time that followed.

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12.

They battled Diantha, after all. Without Greninja, they lost. Or they may have lost anyway. He wasn't sure.

Still, that last battle, between Pikachu and Mega Gardevoir, was without regrets.

They could still get stronger. And they could do it without changing who they were.

But Greninja… he still didn't understand what it had been between them that had tied them together like so?

He knew Greninja was watching from the stands. He'd seen the flash of blue and purple in the crowd, before it was gone. He didn't know what would happen if Greninja used an attack again. Or used Torrent again. Or if they wound up fighting side by side again because he'd be defenceless otherwise, and a part of him was afraid.

But another part of him was relieved the possibility wasn't entirely gone.

He didn't stay too long underwater after that to prove himself right or wrong.