Outside, red chakra burst violently from Naruto's body, rising in waves. His eyes turned red, his fangs grew, and his whisker marks thickened.
"He's losing control again." Kakashi's eyes narrowed.
Naruto stood, chakra roaring around him like a firestorm. The grass burned, and the ground cracked under his feet.
"I'm not weak!" Naruto growled, his voice distorted and mixed with Kurama's.
"Tch. Idiot." Sasuke stood slowly, ready.
"He's going wild again…" Ranmaru covered his eyes.
Kakashi moved in a flash and appeared behind Naruto. "That's enough."
"No! I'm not gonna lose again!" Naruto turned, eyes wild.
Kakashi raised a hand, his chakra calm and vast. "Naruto. Sit."
A wave of chakra pushed Naruto back slightly, and for a second, his body trembled, Kurama's chakra resisting the overwhelming calm of Kakashi's own. But then Kurama grumbled inside the boy's head.
"Fine. Listen to me before I really let you go berserk and grow tails."
Naruto blinked and suddenly the red chakra stopped. He collapsed on his knees, panting.
Kakashi kneeled beside him. "You're improving. You kept your mind this time. But if you let emotion control you, even the fox can't keep you stable."
"I… I just wanted to catch up…" Naruto wheezed.
Sasuke walked over and looked down at him, hands in pockets. "You'll get there. Just stop rushing like a moron."
"You're a moron." Naruto gave a weak glare.
Kakashi watched them and suddenly got an idea.
He stood still, his hand pressed over the seal on his abdomen his custom seal, crafted with the Formula Reconstruction Technique.
The one that he made when he was in the land of waves was designed specifically to absorb and refine foreign chakra. He created it not to depend on borrowed power, but to purify it, and make it his own.
Kurama's chakra, wild and dangerous, flowed like molten fire through his body. But Kakashi didn't flinch. The seal glowed faintly, a circle of intricate symbols revolving in layers. He wanted to absorb Kurama's chakra, refine it through the seal, and integrate it safely into his own chakra network.
Kurama's eyes glared from Naruto's mindscape, his massive form coiled within the cage. "You're really doing it, huh," he growled, his voice rumbling like thunder. This was the second time this brat stole chakra from him.
Kakashi didn't answer. He focused, hands forming a specific sequence of seals. The core sigil on his stomach shifted slightly, pulling chakra in as he maintained contact with Naruto.
Suddenly, waves of deep red chakra funneled through the link, and Kakashi's body lit with crimson veins. It wasn't overwhelming. Not anymore. The seal rotated faster, symbols humming and pulsing as they refined the corrosive chakra, cooling it, calming it, purifying it.
Kurama grunted, observing from within Naruto. "You're a greedy human Kakashi! You just said you wanted some, but you're taking that much?"
Kakashi let out a calm breath. "You're the one with endless reserves. Sharing is caring, isn't it?"
"You're lucky I'm bored," Kurama snorted. "Or I'd turn that silver hair of yours white."
"It already is." Kakashi raised a brow.
Kurama paused. "Tch. Figures."
The air around Kakashi began to shift. A visible aura surrounded him, a smooth, controlled mix of his chakra and the freshly refined Nine-Tails chakra. The sensation wasn't heavy or aggressive like before. It was sharp. Clean. Powerful.
"Your seal actually works," Kurama mumbled in disbelief.
"I thought you'd end up a crisped piece of toast." Still in disbelief at what Kakashi had created.
Kakashi gave a half-smile. "You wound me."
He slowly unclenched his fists. His chakra felt… deeper. He could feel every muscle, every cell humming with potential.
His healing was slightly better. His stamina was stronger than it had ever been. And the most surprising part: his control hadn't dropped at all. It had risen. The balance of yin and yang chakra was perfectly refined, granting him the benefits of a high Kage-level shinobi.
"High Kage…" Kakashi whispered, stunned at the depth. "No wonder you're hard to seal away."
"You gonna write a book about it?" Kurama said dryly. "Call it 'How to Leech from a Fox.'"
Kakashi chuckled and shook his head. "Maybe later."
He lifted his hand, watching red and blue chakra swirl evenly around his fingers. His elemental chakra was more responsive. Lightning sparked with ease. The wind twisted faster.
Behind him, a few birds burst from a tree branch, startled by the shift in his chakra signature.
Kurama, still lounging in his cell, narrowed his eyes. "You really planning to fight 'that' Madara guy, huh?"
"I don't plan to die before that," Kakashi replied. "So yeah. I'm getting ready."
Kurama's eyes narrowed, and after a beat of silence, he said, "Don't get cocky. I'm still way stronger."
Kakashi smiled. "I know."
The seal dimmed, having done its job. The chakra flow steadied, refined, and embedded within Kakashi's own system. There was no burning. No wild surges. Just power steady and sharp.
Kurama yawned. "If you blow yourself up, don't come crying to me."
"No promises," Kakashi replied as he took his hand off Naruto.
Kurama gave one final grumble. "Greedy, silver-haired bastard…"
As Kakashi got up he felt better than ever. He could also feel that his aching Sharingan had healed and the pupil power had recovered as he turned on his slightly blurry left eye had returned to normal.
He was delighted about this as it meant that he could overuse the Mangekyo and it could recover after all the damage.