The void was absolute. No light. No sound. No ground. Luffy floated in an endless, silent blackness. For a moment, panic clawed at him. Then, a golden spark flickered to life in his chest, a tiny ember of Ki he'd learned to cultivate. It pushed the darkness back a few feet, creating a small bubble of reality around him.
"Sunny! Guys!" he yelled. His voice didn't echo; it was just swallowed by the nothing.
Then, he saw them. A few hundred feet away, frozen in a single, silent moment, was his ship. He could see Usopp mid-stumble, Robin looking up with a calm, knowing expression, Sanji holding a pot. He stretched his arm. It elongated, passed through the space, and... touched nothing. His hand went right through the image.
"It's an echo, boy."
The voice came from everywhere and nowhere. It was cold, vast, and ancient. The darkness in front of him coalesced into a shape. A humanoid figure of pure, impenetrable shadow, with two pinpricks of white light for eyes. It had no other features.
"I am the Void that dwells between worlds. The Eater of Echoes. You are an anomaly, a creature whose very existence is a contradiction. Your bond with those beings... it's the strongest echo I have ever tasted. It resonates across dimensions."
"What did you do to them?!" Luffy demanded, his hands balling into fists, the golden aura flaring around him.
"They are not here. They are echoes, memories you project. I brought you here by pulling on that memory. You are the real one. And your energy, the chaotic mix of your body and this universe's power... it is the most delicious echo of all. When I consume you, your very existence will fuel me for eons."
The Void creature lunged, its form shifting into a massive claw of shadow. Luffy dodged, his Dawn Star speed letting him zip through the void. He threw a Jet Pistol, his fist glowing with gold. It passed through the creature's body, doing nothing. It was made of nothing.
"Fool. You cannot touch the void."
The creature reformed, its claws slashing across Luffy's back. He screamed. It wasn't a physical wound, but the feeling of his memories, his energy, being drained. He felt a piece of his fight with Vegeta, a fragment of his training with Roshi, flake away and vanish.
He tried Kamehameha. A torrent of gold energy shot out, dispersing the creature's form for a second, but it just reformed, laughing. "Energy is my food! You only make me stronger!"
Luffy panted. His Dawn Star was flickering. He was alone, in a place with no rules, fighting an enemy he couldn't hit, who was slowly eating him from the inside out. For the first time since Impel Down, true despair began to creep into his heart.
He looked at the frozen image of his crew. He saw Zoro, his eye closed, his hand on his sword, a look of absolute trust on his face. He saw Sanji, a cigarette dangling from his lips, a faint smirk as if he'd just told a joke. He saw Jinbe, his massive arms crossed, a calm, steady presence. He saw Chopper, scared, but looking towards where Luffy would be, ready for his captain to save him.
They're not here. But they're waiting. They're always waiting.
The despair vanished. It was replaced by something hotter, more stubborn than any Ki. It was his will. His absolute, unshakeable conviction.
"You said you eat echoes," Luffy said, his voice quiet but firm. The golden aura around him flickered and died. The Void creature paused, confused.
"Yes. It is my nature."
Luffy grinned. It wasn't a happy grin. It was the grin of a predator. "Then eat this."
He didn't reach for the Ki of this universe. He didn't reach for the power of his Devil Fruit. He reached deeper, past both, to the very core of his being. To the thing that had made him a captain, a brother, a friend. To the echo that the Void itself had just identified.
He reached for his ambition. For his dream. For the promise he made to Shanks, to his crew, to himself.
He pulled on the echo of the King of the Pirates.
A new energy erupted from him. It wasn't blue like Ki. It wasn't gold like his Dawn Star. It was a deep, resonant, Conqueror's Red. It wasn't an attack. It was a presence. It was his very existence asserting itself over the nothingness.
The Void creature screamed. For the first time, it felt pain. The red energy wasn't something it could eat. It was a truth, a reality so powerful it overwrote the void itself. It was the Echo of the One Who Will Be King.
"This... this is not energy! What is this?! STOP!"
Luffy, wreathed in the red haze of his unbreakable will, walked towards the creature. He raised his fist. It wasn't a Gear. It wasn't a Ki technique. It was just a fist, wrapped in the absolute certainty of his dream.
"I am Monkey D. Luffy," he said. "And I will become the King of the Pirates."
He punched the Void creature. His fist connected with its solid, shadowy form. The red energy exploded, filling the void, shattering the creature into a billion pieces of dissolving shadow.
"I don't care what universe I'm in," Luffy said to the dissolving darkness. "My crew is waiting."
The void shattered. The image of the Sunny dissolved. Luffy felt himself falling, tumbling through a kaleidoscope of colors and sounds. He saw flashes of his own world, of the Dragon Ball world, of a thousand others. And then, with a tremendous splash, he hit salt water.
He was in the ocean. The real ocean. Above him, the clear blue sky of the Grand Line. He coughed, sputtering, his body already feeling heavy from the sea water. He flailed his rubber arms, but they were useless.
Just as he was about to sink, a long, blue nose pierced the water, and a familiar reindeer with a blue hat grabbed him by the vest.
"LUFFY! LUFFY! I GOT HIM! I GOT HIM!" Chopper cried, tears streaming down his face.
Luffy looked up. The Thousand Sunny was right there. Nami was crying and laughing on the deck. Sanji was kicking his legs in the air. Zoro was smirking, his one eye open. Usopp was cheering. Robin was smiling gently. Franky was doing his super pose. Brook was playing a joyful tune. Jinbe was at the helm, a wide grin on his face.
They pulled him aboard. He lay on the deck, soaked and exhausted, but with the biggest, dumbest grin on his face. The sun was warm. The sea was salty. His crew was safe.
"Hey," he mumbled. "I'm back."
And as his crew swarmed him with questions, tears, and laughter, a faint whisper touched the edge of his consciousness. It wasn't the Void. It was something else. A voice, gruff and arrogant, echoing from somewhere far, far away.
"Freak... I'll find you again. And next time, I'll be ready for whatever trick that was."
Luffy's grin widened. "Shishishi... see you then, pointy-hair guy."
He had a feeling his adventures in that other world weren't quite over yet.