Percy found himself in a place that felt both familiar and distant. It took only a moment of looking around to recognize it as Camp Half Blood, the place where he had spent so many summers and made unforgettable memories. As he walked through the camp, he was greeted by the cheerful faces of his old friends, each one excited to see him.

"Hey, Percy!" called out Grover, with his signature smile. "Ready for some satyr shenanigans?"

Percy chuckled, enjoying his friend's playfulness. "Always, Grover. Count me in!"

Percy's heart swelled with joy as he spent time with his old friends, relishing every moment. While he felt that something was amiss, he couldn't help but get entangled in everything about this moment. He playfully bickered with Thalia, his cousin and daughter of Zeus, over who was the better camper.

"Come on, Thalia. You know I can beat you in an arm wrestling match any day!" Percy teased, flexing his biceps.

Thalia rolled her eyes with a grin. "Dream on, kelp head. I've got the strength of a goddess on my side."

They laughed, their playful banter a comforting melody to Percy's ears. Next, he found himself at the arena, sparring with Clarisse, the fierce daughter of Ares. Their swords clashed, and though Percy could have easily won the fight, he held back, allowing Clarisse to match his strength.

"You're going easy on me, Jackson!" she huffed, swinging her sword with determination.

Percy grinned. "Maybe I am, or maybe I just want to give you a chance to show off your skills."

Clarisse growled playfully, appreciating the friendly challenge. They continued their duel, the sounds of their swords echoing through the training ground.

Later, Percy tried his hand at archery, but instead of hitting the bullseye, his arrows seemed to go wide, missing the target by a mile. He couldn't stop himself from laughing at his own results. He was never one for archery.

"Wow, Percy, you're really off today," called out Will, the son of Apollo, who was watching from the sidelines.

Percy shrugged, grinning sheepishly. "I guess even the best archers have their off days," he joked.

Despite his poor aim, Percy felt a sense of peace and happiness wash over him. The camaraderie, the laughter, and the carefree moments with his friends were a balm to his soul. For a while, he forgot about the challenges and responsibilities that he had.

Then, Percy found himself eating at the Poseidon table, savoring his blue spaghetti and blue diet coke with each bite. His heart skipped a beat as he felt a familiar touch covering his eyes, and he froze, unsure of what to expect. The voice that followed was like a sweet melody he hadn't heard in far too long. "Guess who?"

Slowly turning around, his eyes widened at the sight of Annabeth standing before him. His breath caught in his throat, and for a moment, he couldn't find the words to speak. She looked just as he remembered her—her radiant smile, her piercing gray eyes, and her golden curls dancing in the breeze.

"What's wrong, Seaweed Brain? You look like you've seen a ghost," Annabeth teased, a playful glint in her eyes.

Percy blinked back tears, feeling a surge of emotions overwhelm him. It was as if a part of him had been missing, and now, it had suddenly returned. But he couldn't understand why he was reacting this way, why his heart felt so full of longing, even though she was right in front of him, like she has always been.

"I just… I thought you…" His voice trembled, unable to form the words. His emotions were a tangled mess, a mixture of joy and sorrow, and he didn't know why. He struggled to find the right words to convey what he was feeling. "I'm just… really glad to see you."

Annabeth's smile softened, and she reached out to gently wipe away a tear that had escaped from his eye. "I'm glad to see you too, Percy," she said softly. "I love you."

They spent hours together, reminiscing about their adventures, sharing dreams and aspirations, and promising to always be there for each other. Percy felt a sense of contentment he hadn't felt in a long time. It was as if time had stopped, and they were back in the carefree days of their youth.

Now, they both laid on the soft sand in front of the beach, the sound of crashing waves a gentle melody to Percy's ears. He wanted to relish in this moment forever, to hold onto the feeling of joy and peace that being with Annabeth brought him.

But then, just as the sun was beginning to set, he heard a faint shout from the sky. "Percy! Wake up!"

Abruptly sitting up, Percy looked around in alarm. Annabeth also sat up, concern etched on her face. "Seaweed Brain? What's wrong?" she asked.

"Didn't you hear that?" Percy's heart raced, and he scanned the area, trying to identify the source of the voice.

Annabeth shook her head, her brow furrowed. "I didn't hear anything, Percy. Are you sure you're okay?"

Percy hesitated for a moment, feeling a bit foolish. "I... I guess it was just my imagination," he said, trying to dismiss the nagging feeling in the back of his mind.

But as he made his way back towards the campfire, where the traditional storytelling would begin, he couldn't shake the feeling that something was off.

As he joined the others around the campfire, his friends welcomed him with warm smiles and friendly gestures. They continued to share stories, laughter, and good-natured banter. But Percy couldn't fully immerse himself in the festivities. He felt a growing sense of unease, a longing to escape the illusion and confront the truth.

He tried to focus on the stories being told, to distract himself from the voice he had heard, but it was impossible. The voice's warning echoed in his mind, reminding him of something but at the same time couldn't really remember it. The more he tried to, the harder it seemed to get, as if something unknown was actively trying to keep him away from his memories.

And suddenly, Percy found himself standing in a vast expanse of fog. It was an eerie, shapeless void that seemed to stretch endlessly in all directions. He strained to remember how he had arrived here, his mind grasping at fragments of memories that slipped through his fingers like mist. The air around him was thick with a sense of disorientation, as if he were caught in the haze between reality and illusion.

As he pondered the unfamiliarity of his surroundings, the mysterious voice echoed again. It was a haunting whisper, faint yet persistent, weaving through the fog and reaching Percy's ears like a distant melody. He furrowed his brow, attempting to grasp the elusive familiarity of the voice. It seemed to carry a weight of urgency, as if it held the key to a truth he desperately needed to uncover.

In his effort to recall, Percy's mind became a canvas upon which images flickered and danced. Faces and places flashed before him, each one a puzzle piece that refused to fit into the larger picture. He squinted, straining to discern the details, but the memories remained elusive.

Without conscious intent, Percy's breathing shifted. It became rhythmic, a controlled pattern that mirrored a discipline he couldn't quite place. His chest rose and fell in harmony, as if his body were acting on its own accord, guided by some unseen force. He felt a strange sense of deja vu, as if he had practiced this controlled breathing in a distant past.

Then, like a beacon in the fog, a vivid image emerged. A majestic mansion stood surrounded by a breathtaking garden, flowers in full bloom, and a tranquil pond reflecting the moonlight. Butterflies danced freely around it, adding a touch to its mystic nature. The sight was both enchanting and familiar, stirring a sense of intrigue within Percy. He felt compelled to move closer, drawn toward the mansion as if it held the answers he sought.

Upon reaching the ornate door, Percy hesitated before pushing it open. The moment it creaked ajar, a flood of memories rushed over him like a tidal wave. His adventures with Tanjiro, Zenitsu, and Inosuke unfolded before his mind's eye – battles fought, camaraderie shared, and the bonds forged in the crucible of adversity.

Percy's eyes widened in realization, and the weight of forgotten moments pressed upon him. How had he let these cherished memories slip through the cracks of his consciousness? The dream began to unravel, and the fog dissipated, revealing the truth obscured by the veils of forgetfulness. The voice, now louder and more insistent, echoed through the newly revealed landscape. He looked around, seeing the Stolls enthusiastically sharing a story of their latest failed prank, but couldn't focus, too dazed by the revelation that this is all a dream.

"Percy! It's me! You have to remember! Those are not your only friends, nor are they real! Please, you have to wake up! Your new friends are in danger and need your help!"

Percy's heart skipped a beat as he finally recognized Emi's voice. The pieces of the puzzle started falling into place, and he finally understood. Everything around him was cautiously made to keep him asleep so that the Oni could attack the Mugen Train. Was that first Oni a mere distraction, then? He felt bitter, realizing that nothing of this perfect moment was real.

The happiness he had felt with his old friends at Camp Half Blood was real, but now it was just an old memory. His heart had found a new place to belong, and these new friendships were just as genuine and precious to him.

Taking a deep breath, Percy felt a mix of emotions wash over him—the longing for his old life, the happiness he had found in this new world, and the uncertainty of what lay ahead. But he knew he couldn't stay in this dream forever. It was time to face reality and reunite with the friends who were waiting for him.

With determination in his eyes, he turned away from the campfire and the illusion of the past. He had to find a way to wake up, to return to the world he had come to love and cherish. He couldn't find the words in his heart to say goodbye to his old friends, even though they are only illusions. So he turned his back and ran as fast as he could.

As he ran his way to the border of the camp, he could hear the voices of his friends calling out to him, pleading for him to stay. But he couldn't let himself be swayed by the illusion any longer. He had to be strong, for himself and for his comrades that waited for him on the other side.

As Percy stood at Thalia's tree, panting heavily, his mind raced with uncertainty. He knew he was dreaming, but the pull of the dream and the memories it held were almost too powerful to resist. He had to wake up, to face the reality that awaited him, but leaving this illusion behind meant leaving behind the happiness he had found here.

The sound of footsteps reached his ears, and he turned to see that Annabeth had followed him, concern evident in her eyes. "Percy, what's going on?" she asked, reaching out to touch his arm gently.

He looked at her, his heart aching at the sight of her worried expression. She felt so real, so alive in this dream, and yet he knew that she wasn't. "Annabeth, I... I have to go," he said, his voice trembling.

"Go? Go where?" Annabeth's brows furrowed in confusion. "Percy, you're not making any sense. You're scaring me."

"I know," he whispered, tears welling up in his eyes. "And I'm sorry. But I can't stay here. This isn't real, Annabeth. None of this is real."

Her grip on his arm tightened, and she shook her head in denial. "What do you mean it's not real? We're here, together, just like we used to be. Don't you remember?"

Percy took a deep breath, trying to steady himself. "I remember, but... it's all a dream, an illusion. I have to wake up and face the truth, no matter how painful it might be."

Annabeth's eyes glistened with tears, and she pleaded, "But why? Why would you want to leave this? We can be together here, just like old times. We can be happy."

A lump formed in Percy's throat, and he struggled to find the right words. "I want that too, Annabeth. More than anything. But this isn't real happiness. It's a lie, a mirage. I can't keep running away from reality."

"But what if this is real?" Annabeth's voice trembled as she spoke. "What if this dream is trying to show you what you really want? What if it's showing you the happiness you've been denying yourself?"

Percy's heart ached at her words, torn between the longing to stay and the need to leave. "I don't know, Annabeth. But I can't stay here forever. I have to find my way back to the real world, to my friends, to the challenges that await me."

He gently pulled his arm free from her grasp, and she looked at him with tear-filled eyes. "Please, Percy. Don't go. Stay with me," she pleaded.

"I wish I could," he whispered, his voice breaking at the sight of her tears. "But I can't. I have to wake up."

And with that, he turned away and ran towards the edge of the camp, his own tears held back by force. His friends called out to him, their voices a mix of confusion and concern, but he didn't look back. He had to keep moving forward, to find a way out of this dream and back to reality.

As he reached the border of the camp, the magic of the dream began to unravel around him. The scenery wavered, the colors fading, and he saw a familiar figure in the distance—Emi, just as he remembered her, smiling warmly at him.

"What took you so long, Percy?" she called out.

He ran towards her, his heart racing with hope and desperation. But as he reached out to touch her, the dream shattered, and he woke up with wide eyes.

He lay there for a moment, his breaths coming in ragged gasps, his heart still heavy with the emotions of the dream. It had been so real, so vivid, and for a moment, he had allowed himself to believe it was true.

But now he knew the truth. He couldn't hide in dreams forever. He had to face the challenges that lay ahead, to confront the reality of his world, and to cherish the memories of the past while moving towards the future.

Percy's eyes were shot open as he looked around his surroundings, only to find the train transformed into a nightmarish scene. The once familiar interiors were now entirely covered in a pulsating and malevolent purple goo, writhing with an eerie life of its own. He felt a shiver down his spine, realizing that this time it wasn't a dream; this was all too real.

"Is this another Oni's doing?" Percy muttered to himself, adrenaline coursing through his veins.

As he rose to his feet with Riptide in his hands, he noticed Kyojuro standing nearby, his face etched with determination. The Flame Hashira had already recognized the danger and was prepared to face it head-on.

"Percy!" Kyojuro called out, his voice a mix of urgency and concern. "It's good to see you awake! Your friends Kamado and boar are fighting on top of the train! Go help them! Yellow boy, the girl demon, and I will protect the wagons!"

With those words, Kyojuro leaped into action, leaving Percy to wonder what kind of danger Tanjiro and Inosuke were facing.

The purple goo pulsated menacingly as Percy made his way through the train, determined to find his friends. The air crackled with dark energy, and he knew that they were not dealing with an ordinary threat.

When he emerged on the train's roof, he was met with a chaotic scene. Tanjiro and Inosuke were locked in a fierce battle with a powerful demon, whose grotesque form seemed to be made of the same malicious goo that now covered the train. There seemed to be multiple hands made out of the goo that reached for his friends, who were trying to hold themselves against it.

Percy rushed to his two companions, cutting the hands that tried to grab him along the way. "What is the situation? Be quick," he urged.

Tanjiro quickly filled him in, "There is another Oni! It is the Lower Moon One! He merged himself with the train, and he wants to kill everyone at the same time! Be careful, he has magic that can put you to sleep if you look at its eyes! We have to reach the front wagon to cut its neck!"

Inosuke, never one to miss a chance for bravado, chimed in, "Which means that the great Inosuke was right from the start! Kneel before me, my underlings!"

Percy shook his head in exasperation, but there was no time for banter. The three of them continued making their way to the front of the train, slashing and dodging the attacks from the grotesque gooey arms.

As they closed in on the main wagon, the number of arms surrounding them seemed to multiply. Percy knew they had to act fast. "Tanjiro, Inosuke, we have to attack at the exact same time. If we cut everything, it will be slower to regenerate. Use any attacks that you have that can cover a lot of area!" he commanded.

Taking a deep breath, Percy focused on his footwork. As the multiple arms reached out towards him from different angles, he maintained his calm and centered himself. "Ocean Breathing… Third Form—Current Spiral."

With deft movements, Percy spun on his feet, gracefully evading all of the attacks and slicing through the arms with multiple strikes as they got closer. But the Oni wasn't done yet; another barrage came from behind, trying to catch him off guard.

Noticing the incoming danger, Percy performed a backspin and jumped backward, narrowly avoiding the attack. He knew he had to act swiftly. "Ocean Breathing… First Form—Wave Crash Slash!" he exclaimed.

With a powerful swing of Riptide, Percy cut through all the arms at once, effectively severing them. The severed gooey limbs wriggled and struggled to reattach, but Percy's swift attack had bought them some time.

As he caught his breath, Percy glanced at his friends, seeing they had the same success as him. They couldn't afford to rest, though. They had to find the Oni's main body and put an end to this threat.

As they continued their run towards the front of the train, Percy's hunch was proven right. The Oni seemed to be focusing all its energy on regenerating and protecting its neck. As they made their run to the first wagon, they weren't bothered by the purple goo anymore.

The train's metal roof clanged beneath their feet as they finally reached the top of the front wagon. Percy looked ahead, and in the dim light, he could see the bulging form of the Oni's neck below them.

"The Oni's neck is right below us," Tanjiro informed, his voice steady despite the looming danger.

Inosuke cracked his fingers, his adrenaline pumping. "Breath of the Beast… Second Fang—Rip and Tear!" With two sharp blows from his twin swords, he effortlessly cut through the thick metal that protected the train, leaving Percy impressed by his sheer strength.

Percy's eyes widened as they beheld the grotesque sight before them—the massive bone surrounded by thick pulsating muscles, guarded by the relentless purple goo. Tanjiro raised and descended his sword, determined to put an end to this Oni's plans, but his sword strikes were met with the same eerie resistance each time, as the goo multiplied to protect its vital spot.

"It's putting all its energy into this defense," Percy remarked, a hint of relief in his voice. "That means the passengers inside the train should be safe for now. We need to find a way to break through this goo and take this Oni down for good."

Inosuke's eyes glinted with determination as he cracked his knuckles once more. "Leave it to me! I'll smash through this goo with everything I've got!" he declared, a fierce fire burning in his heart.

Tanjiro nodded, his determination mirroring Inosuke's. "Let's combine our efforts. If one cuts the goo protecting the bone and the other goes for the neck, we can cut it," he suggested, getting nods of agreement from Percy and Inosuke.

As they prepared to strike, Tanjiro raised his sword, ready to make the first move. But before they could attack, the purple goo rose once more, stopping their plans. Percy's eyes widened as the purple goo's surface sprouted hundreds of eyes, each bearing the kanji for "Lower One." The gaze of those malevolent eyes felt as if they were piercing through his very soul.

A voice seemed to come from everywhere, saying, "Coerced Swooning Sleep: Eyeballs." The drowsy feeling washed over Percy once again, threatening to pull him into slumber. He heard Tanjiro's urgent shout, instructing them to cut their own necks in their dreams to break free from the Oni's control.

"No... not again," Percy thought, trying to fight off the drowsiness that threatened to consume him. He saw Tanjiro's eyes roll back, indicating his sleepiness and leaving only Percy and Inosuke standing against the Oni's power.

Inosuke growled, his voice filled with defiance. "I won't let this goo put me to sleep! My mask will protect me from your magic!" he roared, bringing his swords up in a defensive stance. "I'll slice through anything that comes near me!"

Percy felt the weight of the drowsiness pressing down on him, but he clenched his fists, refusing to give in. He had faced many formidable foes in the past, and this Oni would not be the one to defeat him.

In the face of the Oni's relentless assault on their minds, Percy recalled the lessons he had learned at Butterfly Manor. He closed his eyes, shutting out the chaotic surroundings, and controlled his breathing.

"Clear your mind. Remember your training. Don't let this foreign energy get control you. Focus on your body, mind and spirit. Meditate. Breathe in, breathe out," he repeated in his mind, finding a sense of calm amidst the storm. He let go of the fear and uncertainty, replacing it with the familiar feeling of determination that always surged through him in the heat of battle.

As he meditated, Percy could feel the fatigue slowly dissipating, replaced by a surge of newfound strength. The dream realm's hold on him weakened as he expunged it from his body, and he knew he had to act fast.

Opening his eyes, Percy saw Inosuke and Tanjiro still locked in their own battles against the Oni's magic. Tanjiro seemed to be in trouble, falling asleep and waking up multiple times. In a scary moment, Inosuke had to stop Tanjiro from cutting his own throat, not realizing he was not dreaming anymore. Percy rushed towards them, slashing through the purple goo that attempted to obstruct his path.

From the corner of his eyes, Percy noticed the conductor approaching Inosuke from behind with a pointed object, ready to stab him. In a split-second decision, Percy's instincts kicked in, and he used his water-controlling powers to freeze the air around the conductor's weapon, creating an ice barrier that blocked the attack. The fear was evident on the conductor's eyes, hinting that he might not have been willing on his actions.

Tanjiro looked at the ice barrier with astonishment, clearly puzzled by Percy's water-based abilities. In that moment, Percy realized that he hadn't explained the details of his powers to his new friends yet. It was still a secret only known by the Master and the Hashiras. He quickly called out to Tanjiro, thinking of a plan amidst the chaos.

"Tanjiro! Remember the hand demon back at the final selection? Let's do the same plan! Don't look at anywhere else besides the neck!" Percy shouted, hoping his words would reach him.

Tanjiro nodded, understanding Percy's plan. He took a deep breath, adopting a stance Percy was unfamiliar with, and with the determination of a warrior, he rushed towards the Oni's neck.

Percy couldn't help but wonder if this was the "Dance of the Fire God" that Tanjiro had mentioned before. However, he pushed those thoughts aside and focused on his role – giving Tanjiro the cover he needed to reach the Oni's weak spot.

"Ocean Breathing… Second Form—Tidal Surge!" Percy called out, his voice filled with determination. He moved with incredible speed, executing multiple diagonal slashes to cut through the goo attempting to reach Tanjiro.

As Tanjiro closed in on the Oni's neck, Percy seamlessly switched between his second and third forms, using the versatility of his swordsmanship to keep the goo at bay. He knew that every second counted, and he wouldn't let anything stand in their way. He had only one goal in his mind, one that he was determined to fulfill: stop the goo from reaching Tanjiro and making him fall asleep.

With Percy's cover, it was easy for Tanjiro to reach the neck in no time. Bringing the sword all the way back and swinging it in a wide arc, Tanjiro was able to cut through the thick bone and muscles of the Oni's neck, causing the creature to let out an unbelievable loud screech that pierced their ears. "Dance of the Fire God—Blue Heaven," he said. The victory was palpable in that very moment.

But as the Oni's body shuddered and shook, the purple goo seemed to explode in every direction. The force of the explosion caused the train to jolt violently, derailing from its tracks and sliding through the land before finally toppling onto its side.

Percy, Tanjiro, and Inosuke were not spared from the impact. They tumbled through the dirt, their bodies sore and battered from the crash. As Percy gazed up at the sky, his breaths coming out in heavy pants, he realized that it was almost morning. They had emerged victorious, and soon the first rays of dawn will break through the horizon.

Despite the pain and exhaustion, Percy couldn't help but let out a laugh of relief. Tanjiro, lying tiredly beside him, joined in the laughter. Even Inosuke, who stood up to show off his resilience, couldn't resist cracking a chuckle.

As they caught their breath, Percy noticed the Oni's body slowly disintegrating, evidence of their triumph. The threat was finally vanquished, and they had saved the train and its passengers.

All three of them, sprawled on the ground, began controlling their breathing with the Total Concentration Breathing to ease the pain and fatigue that had settled into their bodies. The battle had been intense, and they were all grateful for the momentary respite.

"Oh, you all learned to constantly adjust your breathing. That's impressive! Very impressive indeed!" Percy heard a familiar voice say, and he looked up to see Kyojuro approaching with a smile from ear to ear. "Everyone is safe," he continued. "There are a lot of injured people, but thankfully, nothing life-threatening. You don't have to punish yourselves any further."

Relief washed over the trio at the news. Their hearts were heavy with the weight of the battle, and knowing that the passengers were safe lifted a tremendous burden from their shoulders.

"We did it," Tanjiro said, a hint of awe in his voice. "We actually did it."

Inosuke grinned proudly. "Of course we did! The great Inosuke wouldn't settle for anything less!"

Percy chuckled, feeling the camaraderie between them grow even stronger. They had come together as a team, facing incredible odds and emerging victorious.

As they began to collect themselves, preparing to report to the corps and assist the injured, a sudden sound caught their attention. Something landed on the ground a few meters away form them, sending clouds of dust into the air. They turned to see a humanoid figure emerging from the dust. It had vibrant pink hair and multiple blue marks across its muscular body.

Percy froze, and all the exhaustion and weariness seemed to vanish in an instant, replaced by a surge of adrenaline. Because on the new arrival's eyes, where its pupils should be, it was written, with one kanji in each eye, "Upper Moon Three".

And suddenly, things just got very complicated.