Our heroes trudged through the dense forest, their journey towards Mount Tensei leading them deeper into the wilderness. They had hoped to stop by a Pokémon centre along the way, but as luck would have it, none were to be found in the vicinity. So, they pressed on, the crunch of leaves and twigs beneath their feet the only sound to be heard. It wasn't until Serena noticed Misty's shivering that they came to a halt.

"Hey, Misty, are you okay?" Serena asked concern etched on her face. Misty's eyes darted around, scanning the bushes and surrounding area as if searching for something.

"Ugh, bugs!" she exclaimed, her voice filled with disgust and fear. Her body shook with each shiver, her arms wrapped tightly around herself in an attempt to keep warm. Serena immediately took notice and offered her a comforting smile.

"Here, we'll hold hands," Serena said with a warm smile. Misty gratefully accepted, her smile returning. Ash and Brock had fallen a bit behind the girls, but Pikachu, still perched on Ash's shoulders, turned around and noticed they were no longer there.

"Pi?", Pikachu questioned.

"What is it Pikachu?", Ash asked, looking back. "The girls! They're not here, Brock!", Ash yelled.

"What?", Brock turned back. But before he could even realize what was happening, Misty and Serena came running out of the forest. Ash turned around to see them, but before he could say anything, Misty punched him on the head.

"It wasn't kind of you to leave us like that!", she shouted at Ash, still panting from the run.

"Here we go again, the usual Misty stuff", Ash groaned, rubbing his head, "But to be fair, you were the one who stopped walking," he added.

Brock, who had been walking ahead of the group, turned around to see what was happening. "Anyways, why did you have to stop?", he asked Misty.

Serena stepped forward, "Misty said she was scared of bugs, so I told her we could hold hands", she explained. Ash couldn't help but burst into laughter at the situation.

"Typical Ash", Brock said, shaking his head with a smirk on his face.

The group continued to walk until they reached a Pokemon centre. Ash sent his Pokemon to Nurse Joy for a quick check-up, while Brock couldn't resist trying to flirt with Nurse Joy, much to everyone's amusement. After leaving the centre, they resumed their journey and soon reached Mount Tensei by evening.

"We're here!", Ash exclaimed, lifting his hand in excitement as he started to run up the mountain. "Wait for me, Ash!", Brock and Serena followed behind him, but it wasn't long before the group became exhausted from the climb.

"Wait up, you three!", Misty called out, panting as she caught up to them. But to their surprise, they had already reached the top of the mountain. Rotom, Ash's Pokedex, flew out of his bag, ready to take pictures of the stunning view. As they looked around, they saw an undiscovered Pokemon emerging from the shadows.

"What is it?", Brock said in amazement, pointing towards the mysterious Pokemon. Rotom quickly scanned it.

"It's not a Kanto Pokemon for sure", Ash said, as Serena clung to him in fear. The Pokemon started to turn around, revealing its true form.

"It's... It's... It's Marshadow," Rotom Dex exclaims in amazement. "The Pokémon I've been searching for. It's an Alolan Pokémon, a fighting and ghost type," Rotom tells Ash about its myth. But the conversation is soon interrupted when Marshadow attacks the gang. It uses a shadow ball on our heroes, and they fall.

"What was that for?" Misty shouts in anger, as she gets up, wiping off the dirt. She was about to reach for her Gyarados, but Ash interrupts her.

"Leave this to me," Ash says, holding a Pokéball and turning his cap. "Greninja, I choose you!" Ash throws his Pokéball.

"Nin!" the Ninja Pokémon appears in full style.

"Whoa! That's new!" Brock says, looking at Ash's Greninja, which is considered his strongest Pokémon.

"Greninja, use Cut!" Ash commands the Ninja Frog, as Marshadow starts to build up another shadow ball.

"Ninja!" Greninja follows the command and cuts through the shadow ball.

"Now, Aerial Ace!"

"Gren...ninja..." Greninja follows the command. Marshadow keeps attacking and starts to use its fighting moves.

"Use Water Shuriken!"

"Gren!" Greninja follows the command, as Marshadow uses Spectral Thief and then Shadow Punch.

"Use Double Team and then Aerial Ace!"

"Ninja!" Greninja hits Marshadow for the first time. Marshadow uses Close Combat.

"NOW GRENINJA, LET'S GET STRONGER TOGETHER, STRONGER, STRONGER AND... STRONGER!", Ash cries out with determination as a body of water starts to surround Greninja, engulfing the Pokémon in a swirling vortex. Suddenly, Greninja's form starts to change, as it takes on a powerful form.

"What is happening?" Misty asks with a confused expression, her eyes wide with amazement.

"Looks like Greninja is Mega Evolving... wait, it doesn't have a Mega Form!" Brock tries to reply, but he is equally as bewildered.

"They're doing it!" Serena exclaims with excitement, her eyes sparkling as the body of water forms a large Water Shuriken on Greninja's back.

"What is that thing?" Misty says with amazement, her jaw dropping in shock.

"We call it Ash-Greninja! And it's only possible because of the bond the two have grown between themselves," Serena replies, her voice full of awe.

"Greninja, use Aerial Ace, and then Cut!" Ash commands, his voice firm and confident.

"Ninja!" Greninja responds with a fierce roar, as it executes the commands flawlessly.

"Now, Water Shuriken!"

"Nin!" Greninja responds, as it fires a massive water shuriken at Marshadow.

"Now, it's time to end this!" Ash starts his Z-Move, and Marshadow faints. The whole team runs towards the fainted Marshadow, and Brock starts to treat it with a sense of urgency.

Ho-Oh appears from the sky, its majestic presence drawing the attention of all. Ash notices it and walks towards the legendary Pokémon with a sense of reverence. The others try to follow, but Brock stops them with a firm hand.

"It's his problem, we shouldn't involve," he says, as Ash starts to float towards Ho-Oh.

The time around Ash and Ho-Oh starts to freeze, and no one is moving, except for Ash and Ho-Oh. Then, suddenly, the surroundings change. Ash is now facing the Earth, and the vision zooms onto a young Ash, who is searching for a Poliwag. Before he can find it, it startles Serena, and then he sees Serena crying alone in the forest. He helps her get out of the forest with a sense of compassion. Then, time passes by, and Ash sees a grown-up version of himself, he was on a plane to Kalos. Quickly, the image zooms out. Ash is now looking at Modern-day Kalos.

As Ash's mind travels back in time, he is struck by the stark contrast between the lush, verdant forests of Kalos he sees now, and the dark, smouldering ruins that lay before him. The once-beautiful landscapes were now consumed by raging infernos, the smoke and ash clouding his vision. In the distance, he spots a figure, a man who looks eerily similar to himself. Another voice calls out to the man, addressing him as Satoshi. Ash's eyes are drawn to a Pokémon, standing beside the man, that bears a striking resemblance to his own Ash-Greninja.

As the vision unfolds, Ash sees that the war has ended, and Satoshi sets sail for Kanto, while Greninja remains behind in Kalos. The Greninja continues to do good in Kalos, and Ash learns that this Greninja is the same one that saved the Ninja village.

As time marches on, Ash witnesses the formation of criminal organizations, the earth losing all hope for peace. He sees trainers emerging from different regions and places, particularly in Kanto where Samuel Oak chooses his starter from his father, Professor Oak, and starts on his journey, to becoming a great trainer. Blue Oak, a new trainer who looks a lot like his son, Gary Oak, emerges, he chose his Pokémon from his grandfather since Samuel did not return from his journey. Along with Blue, three other trainers emerged, Red, Leaf and Tajiri. Red was the first Pokémon master and an amazing battler. But the four trainers had a disastrous fate, after a glorious life. After finding out about his son's death, Samuel Oak returned from his journeys, and followed his family line and became a Pokémon Professor in Kanto.

As Ash watches the world around him crumble, with criminal masterminds now ruling the earth, he sees a glimmer of hope. On the same day, Ash Ketchum is born, an egg from the lineage of Ash-Greninja hatches in Kalos and an abandoned Pichu is left at Oak's laboratory.

And, a spark of new life ignited within Grace, Serena's mother, as she learned of her pregnancy. Ash's mind was flooded with memories, a whirlwind of flashbacks from his childhood to the present moment. He saw himself growing and maturing, watched as Serena and Froakie grew alongside him, and marvelled at the evolution of Pichu into the beloved Pikachu. The visions came in a dizzying rush, culminating in a glimpse of a future confrontation with the powerful Dragon Tao. As the vision began to dissipate, Ash was enveloped in a brilliant white light, and a voice whispered in his ear.

"Ash!", the voice boomed, as the image of Ho-Oh took shape before him. Ash stared in confusion and wonder, unsure of what was happening.

"Who are you?", he asked tentatively.

"Ho-Oh", the image replied, its voice deep and powerful.

"Ho-Oh?", Ash repeated, his mind reeling.

"Yes, Ash. I have seen the future. YOUR FUTURE", Ho-Oh emphasized.

Ash's thoughts raced as he tried to understand what was happening. "Is that why you've shown yourself to me? To protect me from threats?"

"The answer to your question awaits, young man. Follow me", Ho-Oh said, gesturing towards a distant land where new land was being formed. Without a word, Ash followed the image, and as they reached the land, Ash saw many familiar faces. His ancestor Satoshi and his Greninja, Red and all his Pokémon, Sir Aaron and his Lucario, Ash's father, and finally Arceus.

"Dad!", Ash runs towards his father.

"Ash!", Ash's father tells him hugging him, "How's Delia?", Ash's father asks him.

"She's great Dad", Ash tells his father.

"All these people here, we want to tell you something son, so, listen carefully", Ash's father tells pointing at all the others present.

"Ash Ketchum, the one chosen by many! We have been eagerly awaiting your arrival, although it was supposed to be on the day you first set out on your journey. But, better late than never, we say. Welcome Ash, to the Hall of Origin," Arceus says as Ash looks around in awe at the familiar faces. "You have been chosen to join the ranks of the greatest trainers in history, those who have left a lasting impact on the world of Pokémon."

Ash is in shock, unsure of how to react to this revelation. "But why me?" he asks.

"Because you have the potential to become one of the greatest trainers of all time," Arceus replies. "You have the strength, the courage, and the bond with your Pokémon that is necessary to make a difference in the world. But it is not just your strength that has earned you this honour, it is also your compassion and your willingness to help others. You have a heart of a true Pokémon master."

Ash looked at Arceus with a mixture of confusion and wonder etched on his face. "What do you mean by that?" he asked, his voice filled with uncertainty.

"You were born with a purpose, Ash, and that purpose is to bring hope to the world. You have already faced many challenges and overcame them all, without even realizing that it was your destiny," Arceus continued, his voice filled with conviction. "Evil is everywhere and it is your responsibility to protect the innocent from them."

"But what if I didn't want to become a trainer?" Ash questioned, a hint of doubt creeping into his voice.

"You were meant to be a hero, champ," Red interjected, a hint of admiration in his tone. "It was your fate to become a trainer."

"Yes, Ash. You always wanted to be the very best like no one ever was. The well-being of Pokémon was always your destiny, and you've got best friends in a world you must defend - the Pokémon World," Satoshi added, his voice filled with pride.

"Ash, you are the chosen one. You are the only Aura Guardian alive," Sir Aaron said, his voice filled with awe.

"Even before you joined the Ultra Guardians, you were always meant to be the one and only true Ultra Guardian," Ash's father added, his voice filled with pride.

"The true hero," Ho-Oh added, his voice filled with reverence.

"Ash, always remember, we will be there by your side. You can always talk to us through your Aura," Aaron told Ash, his voice filled with warmth.

"With that said, be careful, my son, and take care of your mother," Ash's father added, his voice filled with love.

Ash looks around at all the familiar faces, feeling humbled and honoured to be among such legends. "I will do my best to live up to your expectations," he says, determination in his voice.

"I know you will," Ho-Oh says with a nod. "And remember, you are not alone on this journey. You have the support of all those who came before you, and you will have the support of those who come after you. Together, you will make a difference in the world of Pokémon."

"Ash, just one more thing. On your way back home, go to Cerulean Cave and meet my old friend. Tell him I sent you," Red told Ash, his voice filled with excitement. Ash nods, understanding the weight of this responsibility. He turns to leave the Hall of Fame, ready to continue his journey as a Pokémon master, with the support of the greatest trainers in history behind him.

With that, they all departed. Ho-Oh transformed back into its normal form, and Ash found himself back in the place where the vision had started. The weight of his destiny was heavy on his shoulders, but with the knowledge that he was not alone and the support of his loved ones, Ash knew he could face whatever challenges lay ahead.

As Ash walked away, Ho-Oh watched him with a sense of pride and contentment, knowing that Ash had what it takes to make a difference in the world of Pokémon. Time started to run again, and everything returned to normal. Ho-Oh then flew away, leaving Ash behind. Ash, who was still levitating, suddenly fell, only to be caught mid-air by Greninja with a swift and graceful movement.

Greninja gently placed Ash on the ground, Ash's feet landing softly on the grassy earth. Ash turned to look at his friends, with a smile of gratitude and appreciation on his face.

"Serena, Pikachu, Greninja!", Ash exclaimed, pulling them into a warm and heartfelt hug. "I'm so incredibly grateful that I met all of you."

"What happened, Ash?", Serena asked, her voice filled with confusion. Ash broke the hug and looked deep into Serena's eyes, there was an awkward silence for a few moments as Ash tried to find the right words to describe his vision. Ash then hugged her tightly, and Serena, surprised at first, returned the hug with just as much warmth and affection. Misty and Brock both chuckled, happy to see their friend in such a joyful and content state.