Naruto: God Reborn

Chapter 15: Unleashed Instincts

Unohana steadied herself, her chest rising and falling with controlled breaths. The battlefield was a ruinous expanse, a testament to their clash. Blood dripped from her blade, pooling beneath her feet before rising unnaturally to swirl around her in serpentine trails.

Aizen studied her, his posture relaxed but his crimson blade humming with restrained power. "Still standing? I'll admit, you've exceeded my expectations, Captain Unohana."

Unohana smirked, wiping the blood from her lips. "You should know better than to underestimate me."

Aizen's eyes glinted with amusement. "True."

Her smile deepened, and with a sudden burst of speed, Unohana surged forward, her speed creating a shockwave that shook the ground beneath them. Aizen raised Kurama to meet her strike, the clash of their blades igniting sparks of crimson and black reiatsu.

Unohana twisted her wrist, breaking the blade lock, and spun low to slash at his legs. Aizen leaped back effortlessly, but the blood surrounding her surged forward like sentient tendrils, aiming to ensnare him.

"Interesting," Aizen remarked, sidestepping one of the tendrils before slashing through another with Kurama. However, his blade sizzled upon contact, the blood eating away at the reiatsu surrounding it.

"You noticed," Unohana said coolly. "The blood of Minazuki is no ordinary substance. It corrodes and consumes all it touches. Even your precious Zanpakutō isn't immune."

Aizen frowned slightly, inspecting Kurama. The blade's aura flickered but quickly reasserted itself. "Interesting... but futile. Do you truly think this will stop me?"

Unohana didn't respond. Instead, she pressed her advantage, attacking relentlessly. Each strike of her blade was precise and lethal, her movements a masterclass in swordsmanship. The blood around her acted as both offense and defense, lashing out at Aizen whenever he attempted to counter.

Aizen parried her strikes with measured precision, his every movement deliberate. The spectral fox surrounding him roared, its tails whipping out to intercept the blood tendrils. The battlefield became a chaotic storm of crimson and fiery energy, each collision tearing the ground apart.

Despite his composure, Aizen couldn't help but notice something unsettling. Every time he landed a blow on Unohana, she would heal instantly, her wounds closing before his eyes. Her reiatsu remained steady, undiminished by the ferocity of their exchange.

"You've grown more tenacious," Aizen admitted, deflecting another strike. "Constant healing... you truly are a monster."

Unohana's smile turned feral. "It's not just healing, Aizen. I thrive in battle. The longer this continues, the more dangerous I become."

Aizen's eyes narrowed. "Then I suppose I'll have to end this quickly."

He raised Kurama, the blade pulsating with fiery energy. With a slashing motion, he unleashed another barrage of crescent-shaped reiatsu slashes. Unohana countered by raising a wall of blood, the acidic substance absorbing the attacks with a violent hiss.

Before the smoke cleared, she emerged from the blood, her blade aimed directly at his throat. Aizen sidestepped, but she pivoted, slashing at his stomach. The blade grazed him, her blood searing his body and leaving a shallow wound.

Aizen frowned, retreating a step. He looked down at the wound, watching as it sizzled but failed to spread. "Impressive. But not enough."

Aizen ordered the fox to devour Unohana, the spectral fox's head lunged forward to bite down on Unohana. She leaped back, her blood forming a protective barrier around her.

"Are you enjoying yourself, Sosuke?" she asked, her voice calm despite the ferocity of their battle.

Aizen smirked. "More than I expected. But I believe it's time we conclude this."

Before Unohana could respond, Kurama's reiatsu spiked to an unimaginable level, the air itself growing heavy with it's power. The crimson aura around Aizen expanded, enveloping the battlefield in a fiery storm.

Unohana's eyes widened slightly, her instincts screaming that something big was coming.

"Bankai..." Aizen said, his voice echoing with authority. "Annihilate, Kurama no Ōkami."

The crimson blade dissolved into pure energy, engulfing Aizen in a massive cloak of black and red reiatsu. From the swirling chaos emerged the towering form of the nine-tailed fox, its eyes glowing with predatory malice. Aizen hovered at it's core, his figure wreathed in fiery energy.

Unohana froze for the first time, her smile vanishing as she stared up at the beast. "This... is your Bankai?"

Aizen's smirk widened. "Surprised, Unohana? You should be. After all, in our previous lives, I never achieved Bankai."

The fox roared, its tails thrashing wildly and creating shockwaves that rippled through the battlefield. The sheer pressure of its presence was enough to crack the ground and force Unohana to brace herself.

"This power..." she murmured, her voice barely audible.

Aizen raised one of the fox's massive claws, pointing it at her. "Come, Unohana. Let's see if even you can withstand this."

To be continued...