Multiversal Manifestation System

As the announcement concluded, Wang Zi exited the virtual world, his consciousness snapping back to reality. He sat up on his bed, the faint hum of his home's machinery filling the silence.

Stretching his arms with a groan, he stood and made his way to the mirror in his room. His reflection stared back at him.

A body packed with fat, a far cry from the frame he'd once had.

He furrowed his brows, running a hand through his hair. The strands shimmered faintly in the dim light, the deepening shade of red catching his eye.

"Hmm... Red hair, the Uzumaki Blood huh. I look more like Yahiko than Nagato though, minus the red hair." he muttered, leaning closer. 

With a shrug, he stepped back. "Not that it matters. Yahiko wasn't handsome, but he wasn't ugly either." He smirked. "If anything, it's a decent look for now. But this fat body... Its starting to get annoying."

Wang Zi turned away from the mirror and headed to his living room. Exercise machines lined the walls, each one beckoning him to work off the mass he'd packed on.

"It's time," he said to himself, cracking his knuckles. "Let's shed this weight and wrap up Demon Slayer. Two movies to finish the series quick. That should leave a couple days before the competition's final stage. I'll release one right before after the competition, and the other... Maybe a week or two later."

He glanced at his holo-watch, pulling up a mental checklist. "Workout, animate, plan for the survival round. Simple enough."

"Oh. And meeting the man himself, upgrading the Rinnegan. Let's get that out of the way first."

"System, is it possible to manifest Rengoku, the real one not a puppet, but not permanently?"

"No Host. The character does not have a body, his soul would dissipate quickly when in contact with mana. It is possible if its in the virtual world."

"Ah. Whatever, that works. let's meet him then." Wang Zi went back to his bed and relogged into the Virtual Brain, making his way to the MMS shop. He had the system make an upper floor that was not accessible to anyone besides himself.

As soon as he got to the room and made sure everything was locked, he sat down and had the system summon the man himself, Rengoku Kyojiro.

"System, summon him. 5 hours should be enough for our first talk. How much SP?"

"If the Host does not intend to have a manifestation fight, then the cost would be 1m SP per hour. Totalling 5m SP for 5 hours. Will the Host continue?"

"Sounds reasonable... Fine then. Manifest Rengoku Kyojuro, the Flame Hashira."

As the familiar surge of power coursed through him, the room filled with an intense warmth, as though the sun itself had descended. The light coalesced into a figure - a tall man with flowing blonde and red hair, his eyes burning with unwavering determination.

Before Rengoku could speak, the system's mechanical voice chimed:

DING!

"Congratulations to the host for completing a hidden quest!"

Wang Zi paused, his brow raising in curiosity, but he quickly dismissed it, focusing instead on the man before him.

Rengoku's hand instinctively moved to his waist, but his expression stiffened when he realized his Nichirin sword was missing.

"Where am I?" Rengoku demanded, his tone firm but edged with caution. His stance shifted slightly, prepared for a fight despite being unarmed.

"Who are you? How am I alive?"

Wang Zi raised both hands in a placating gesture.

"Relax. My name is Wang Zi, and you're not in danger. Please, sit down. I'll explain everything."

Rengoku didn't budge, his fiery gaze fixed on Wang Zi.

"I remember my death. Akaza... I fell protecting those passengers. How is it that I am here?"

Wang Zi sighed. "You did die. That much is true. But you're here now because I summoned you."

"Summoned?" Rengoku's voice was heavy with suspicion. "For what purpose?"

"Rengoku," he began, his tone calm but firm, "this world, this universe, is in danger. Just like your world faced the demon threat, mine faces something worse: the Silent Ones, creatures that seek to eradicate all life, not just on this planet but across the entire universe."

Rengoku's eyes narrowed, his stance shifting.

"Exterminate all life? Such a thing cannot be allowed to happen! But... I do not understand. Where is this place? What is this world?"

"I figured you'd be confused. Your world's vision was... limited." Wang Zi sighed. 

"Hua'er, instill knowledge of the current universe's situation into Rengoku. You can do this much right?"

"Of course master! Leave it to me!" Wang Zi's little fairy showed up, starling Rengoku.

But he didn't have time to react before Hua'er suddenly appeared in front of his face, a hand on his head.

Rengoku suddenly stiffened, his eyes widening as a flood of information surged into his mind.

"The universe..." Rengoku whispered, his voice tinged with awe and disbelief. "So vast... so many worlds... and the Silent Ones..."

He clenched his fists, his body trembling slightly as he processed the enormity of it all.

"Even so," he said, his voice steadying, "I cannot abandon my world. My duty is to protect humanity there!"

Wang Zi expected this.

"Sit," he said, gesturing to the couch. "Let me show you something."

Rengoku hesitated but complied, his gaze fixed on Wang Zi as he began to play the Demon Slayer anime.

Rengoku's expression shifted from curiosity to shock as he watched.

"How... how do you know of my world? This!"

Wang Zi nodded. "It's not just your life. It's your future. Watch."

When the scene of Rengoku's death against Akaza played, the Flame Hashira stiffened, his breath catching in his throat.

The vision of his mother appeared, her words echoing in his ears once more:

"You did a wonderful job."

Tears streamed down his face as the memory of his death surfaced. His hands trembled, blood threatening to flow from how hard his nails were biting into his skin.

"Mother..." He whispered.

Wang Zi remained silent, allowing Rengoku to process the emotional weight of his story.

As the anime progressed, showing the deaths of the other Hashira and their desperate battle against Muzan, Rengoku's tears turned to helpless frustration.

"My comrades... we sacrificed so much..."

Wang Zi placed a hand on his shoulder, his tone calm but resolute.

"I didn't show you how it ends, because it's still being written. Your world may be gone from your perspective, but there's a chance to protect others here. If you fight with me, you can honor your comrades by ensuring that no one else suffers the way you all did."

Rengoku remained silent, his fiery eyes fixed on the screen. He didn't speak, but the resolve in his gaze told Wang Zi that the Flame Hashira was at least considering it.

"System, manifest Rengoku Kyojuro's Nichirin sword." Wang Zi said, his voice calm.

With a brief glow, the weapon materialized in Wang Zi's hand. The hilt was wrapped in red and gold, and the blade shimmered like molten fire, its inscription reading: Slay Demons.

Rengoku's eyes widened in shock.

"My sword..." he whispered. His fingers twitched instinctively, as if aching to hold it.

Wang Zi stepped forward, extending the blade hilt-first toward Rengoku. "Here," he said. "It's yours."

Rengoku hesitated, staring at the sword before reaching out and gripping it tightly. As his hand closed around the hilt, a familiar sense of purpose surged through him, and his stance straightened.

Rengoku's fingers ran along the blade, his fiery eyes lifting to meet Wang Zi's.

"Why? Why are you doing this? I don't understand you or this place, yet you... trust me?"

Wang Zi's expression softened. He took a step forward, locking eyes with the Flame Hashira. Without warning, he raised his hand and firmly tapped Rengoku's chest, right over his heart.

"Set your heart ablaze," Wang Zi said, his voice carrying the same conviction that Rengoku himself had used in his final moments against Akaza.

Rengoku froze, the weight of those words crashing down on him like a tidal wave. He stared at Wang Zi, his grip tightening on his sword.

Wang Zi continued, his tone unwavering. "The fight against the Silent Ones is bigger than anything you've ever faced. But if you still believe in protecting others, if you still hold that fire in your heart, then stand with me. Fight not just for your world, but for all worlds."

Rengoku's throat tightened, his fiery resolve flickering as conflicting emotions warred within him. He gripped his sword so tightly his knuckles turned white, staring at the ground as he tried to process Wang Zi's words.

Wang Zi stepped back, giving the Flame Hashira space.

"Take your time," he said. "You don't have to decide now. Watch the rest of this."

He gestured toward the screen, where the Demon Slayer anime paused, waiting to resume.

"It's your story. Your life. Your choices. You'll see things you recognize, and maybe some things you don't. When you're ready, we'll talk."

Rengoku looked up, his fiery eyes still clouded with doubt but tinged with gratitude.

"Thank you... for giving me this chance."

Wang Zi nodded, a faint smile tugging at the corner of his lips. "You deserve it."

He turned and left the room, leaving Rengoku alone with the flickering light of the screen and the weight of his memories.

As the anime replayed, showing scenes of camaraderie, sacrifice, and resolve, Rengoku's fiery gaze softened. He watched intently, his grip on his sword loosening as he absorbed every moment.

When the screen displayed his own death once again, he flinched, his breath catching in his throat. The vision of his mother appeared aswell, her gentle smile shining through the flames.

"You did a wonderful job."

Tears streamed down his face once more, but this time they carried a different weight. They weren't just tears of sorrow, they were tears of determination.

He remembered his mother's teachings...

"People who were born and blessed with greater abilities than others, have to use their power for the world, for the people. Hurting others with your power which was gifted from the heavens, and soiling your clothes is unforgivable. I will not be alive for much longer. It was a blessing to become the mother of such a strong, gentle child.

The Rengoku Family has hunted demons for generations. And becoming Hashira is our pride. Like your father, you will become a great Hashira.

Bear the flame in your heart. Burn evil demons and shine gently on human beings. Hold your heart a flame like the sun. Become the Flame Hashira."

"I won't let that flame die," he whispered to himself, gripping his sword tightly once more.

"Not here. Not anywhere."

As Rengoku continued to watch, Wang Zi finally turned his attention to the system.

"System," he thought, his mental voice sharp. "What's this hidden quest reward?"

The interface flickered to life, displaying the details:

"Hidden Quest Completed: "A glimpse into reality"

Objective: Manifest the soul of a character from the Host's works into the real world.

Reward: Reverse Manifestation

Description: The host has unlocked the ability to manifest themselves into worlds they have created. The world must be at least 70% complete in reality for this function to be activated. While within the world, the host can interact freely, as if it were the real world. Time in the real world will NOT pause during the host's manifestation."

Wang Zi blinked, his mind struggling to process the implications of what he'd just read.

"Reverse Manifestation..." he muttered aloud, pacing the room. "I can manifest myself into the worlds I create?"

The realization hit him like a tidal wave. His pacing slowed, and a smile tugged at his lips before spreading into a full-blown grin.

"This changes everything!" he exclaimed, his voice echoing through the room.

Hua'er, his fairy assistant, appeared by his side, her wings fluttering softly as she tilted her head curiously. "Master, why are you smiling like that? What's so special about this ability?"

Wang Zi gestured animatedly.

"Don't you see, Hua'er? If I can enter the worlds I create, I can do more than just summon characters from them, I can influence them directly! I could help Rengoku save his comrades, guide them to a better future... I could change everything!"

Hua'er's eyes widened.

"But Master," she said cautiously, "wouldn't that disrupt the original timeline of the worlds you create? The events that make them so beloved might not unfold the same way."

Wang Zi waved her concern aside.

"That's the beauty of it. I don't have to change the stories. The audience doesn't need to know how the world is actually like, because they'll never go there.

To them, the stories will remain the same. But the worlds themselves... they don't have to follow the story I write do they? I'll try my best not to alter them TOO much, but I will certainly change some things!"

His mind raced with possibilities. If he could prevent Rengoku's death, help the Hashira survive Muzan, or even bring people back to life with the Rinnegan, the future of those worlds would be completely altered.

"And who's to say that changing things wouldn't lead to new abilities or techniques being discovered?" Wang Zi mused, his grin widening.

"If I intervene, I might trigger events that make these characters even stronger than they were originally written."

The thought of stepping into his favorite worlds sent a thrill through Wang Zi. His dream of assembling a team of the greatest characters from anime, manga, and stories he admired was no longer just a fantasy, it was a goal.

"And with the Rinnegan," he whispered, a glint of excitement in his eyes,

"if it works there as it does here... I could bring people back. They might be gone in their world, but they don't have to be in mine."

As he glanced back at the room where Rengoku was still watching Demon Slayer, Wang Zi's grin softened into a genuine smile.

"Rengoku," he thought, "looks like you'll be returning home after all."