Naruto stood on a broken battlefield, his body glowing red with chakra. Baryon Mode, a mix of his and Kurama's energy, burned bright. He fought Isshiki Otsutsuki, a strong enemy threatening Konoha. Each hit used Kurama's life, like fuel in a fire. Naruto, the Seventh Hokage, battled to save his village. The cost was heavy. "Kurama, we can't do this for long!" he yelled.
"The life needed was mine, Naruto," Kurama said. His deep voice grew weak. The huge fox, sealed in Naruto's inner world, started to fade. A strange calm filled his words.
"Kurama?" Naruto's mind went empty. He watched the Nine Tails, his tailed beast, vanish slowly. They had argued since Naruto's birth, disliked each other, then worked together. Kurama was always there. Now, he was leaving to save Naruto. Sharp pain hurt Naruto's chest. He was Konoha's hero, who saved the world. But now, he felt like that lonely yellow-haired kid again. Fear held him. He fell in his mind, wanting to shout for Kurama to stay. No words came.
Kurama lifted a big paw and held it out. Their habit. A fist bump joined them, always.
Naruto stared at the blurry paw. His eyes burned.
After a wait, he reached out. His small fist touched Kurama's huge one. A soft snap sounded.
Naruto woke on the battlefield, tired. Isshiki was gone, beaten. But the Nine Tails' chakra was missing from his body. "Kurama," he whispered, helpless.
Kurama's mind faded. As a tailed beast, a chakra being, he could not truly die. His chakra would collect over time, bringing him back. Since the Sage of the Six Paths made him, Kurama had never died, only been sealed. He might return, but when? His last thought was to see Naruto again, soon.
Then, Kurama's awareness stopped. But in a moment, it came back. A heavy, bad aura pressed around him, like a cage. "What is this? Am I back?" Kurama growled, confused. His body was weak, half there. "Who did this to me?"
Anger grew, but pain hit harder. Black mist spun, thick with strange, uneasy energy. It felt like a prison, made to hurt. Was this a trap for his return? The feeling was bad, yet familiar. Hidden chains held him. Evil forces moved nearby. Kurama roared, "Naruto, something's wrong! What's happening?"
No answer. The perfect Jinchuriki bond with Naruto was gone.
A cold fear sank in. Had too much time passed? Was Naruto gone?
Kurama's head dropped. Then, a faint signal hit him. "Huh?" His fox eyes widened. He sensed Naruto, weak, full of fear and wonder, but alive.
Joy filled Kurama. He ignored the odd feelings in the signal. With his little strength, he pulled Naruto to him.
"Ah!" A scream sounded. Yellow hair and six whisker marks appeared. It was Naruto, but tiny, shaking, eyes wide with fear. He pointed at Kurama. "Monster!"
The small Naruto jumped up, running in circles in the dark void. Kurama focused again. He swung his tail, hitting the ground. A boom shook the space. Naruto tripped, falling face-first.
"Ow! What was that?" Naruto rubbed his red nose, tears in his eyes. Pain made him forget fear. He stared at Kurama. "My nose is bleeding!"
"Calm down," Kurama snorted. His breath pushed Naruto back, making him stumble. "This is your inner world. There's no real body here. You imagine the pain. Stay calm. I won't hurt you. Your fear makes you weak. One puff, and you fall."
"Huh?" Naruto stood, wiping his face. He seemed to miss Kurama's words. His fear faded. The cold mist grew thin.
Naruto turned. His blue eyes met Kurama's, serious and clear.
Kurama looked at him. A short scarf, crooked goggles, and an orange-gray jacket with a swirl patch. This was Naruto, three or four years old.