Reincarnated As Shiba Clan’s Heir! (Bleach-Gin)

Isshin's Zanpakuto glowed with an intense light before morphing into its Shikai form. The blade elongated and curved, with jagged edges that appeared to emulate tongues of fire. At its core, the weapon seemed to harbor an ever-burning ember, casting an otherworldly glow in the moonlight.

"Things just got a little hotter," Isshin quipped as he adjusted his grip on Engetsu.

Kazuki's eyes flicked to the transformed weapon but remained unflinchable. "I'm still here, aren't I?"

With a battle cry, Isshin propelled himself toward Kazuki using Shunpo, appearing before him in a split second. Their swords met in another fierce clash, the meeting of the blades generating a burst of fiery sparks. Isshin's Zanpakuto seemed to imbue his swings with a greater force, as if it was fueled by an inner flame. Kazuki countered, his own blade shining in response to Engetsu's fiery form, absorbing and deflecting the energy.

Seizing the opportunity, Kazuki pushed back with equal force, disengaging their locked blades and creating enough distance to give him room for his next move.

"Hado Number Thirty-Three: Sokatsui!"

A surge of blue energy emitted from Kazuki's palm, aimed directly at Isshin. Isshin smirked and deflected the energy with a casual wave of his Zanpakuto. The spiritual energy scattered into a harmless burst of light.

Using the Hoho technique, Kazuki suddenly closed the distance between them, his blade seeking its mark. But Isshin was ready. He spun, and with a swift, upward slash of Engetsu, deflected the strike, sending Kazuki back a few feet.

As they circled each other, the atmosphere became dense with their exerted spiritual pressures. The ground beneath them appeared to almost tremble, and the air vibrated with their intense focus.

"Looks like we're on an even playing field," Kazuki said, sweeping his Zanpakuto horizontally to his side, its edge emanating a shimmering aura.

"That's what makes this fun," Isshin replied, lunging forward with renewed energy.

They clashed again, blades ringing in the night air. Isshin incorporated his Shikai’s ability into his technique, each strike generating a trail of fiery embers. Kazuki deftly parried, but the residual heat was beginning to take its toll. He felt the warmth seeping into his blade, the edges beginning to glow an unsettling orange.

Kazuki backed off, disengaging from the melee, taking a moment to regain his focus. Isshin seized the moment and aimed his blade toward the ground.

"Bakudo Number Thirty-Six: Shitotsu Sansen!"

Three yellow beams shot from Engetsu's blade, embedding themselves into the ground in a triangular formation around Kazuki. A sudden binding force emerged, attempting to hold him in place.

Reading the intent, Kazuki moved, darting outside the triangle just in time as it solidified into a crystalline structure. A split-second delay would've imprisoned him.

"Close, but not enough," Kazuki taunted.

"Who said I was done?" Isshin grinned, using Shunpo to reappear behind Kazuki, his fiery blade arcing through the air in a wide swing.

But Kazuki had anticipated it, and with a burst of Hoho, he repositioned himself to meet Isshin's attack with his own. Their swords collided in a burst of energy that illuminated the field, shadows stretching in every direction.

This time it was Kazuki who took the offensive, his strikes more deliberate and precise. Isshin barely managed to deflect a slash aimed at his torso, the force of the blow staggering him.

Seeing the momentary lapse, Kazuki leapt into the air and, using Shunpo, disappeared, only to reappear behind Isshin.

"Your turn to keep up," he murmured, his sword descending toward Isshin's shoulder.

"Then it's time for you to see Kamijō Tenseiga." As he said that, Kazuki aimed its tip at Isshin and called out, "Devour, Kamijō Tenseiga."

Only his closest friends knew his true Zanpakuto, Kamijō Tenseiga. The number wouldn't pass the number on two hands. Among them were Kukaku, Yoruichi, Lisa, Isane, Mashiro, Kensei, Isshin, and the head of the Shiba Clan, Kengo. Everyone else only knew its half-released form, Shinso.

Upon his utterance, the elegant katana transformed. The blade elongated, radiating an ethereal light as though it was woven from starlight. The handle darkened, contrasting vividly with the now radiant blade. The sphere at the end of the hilt began to emit a soft, cosmic glow. To those who were familiar, it was a sight to behold, an elevation from its usually reserved form.

Isshin eyed the transformed weapon, then looked at Kazuki. "Ah, finally showing me what you've got."

"You could say that," Kazuki replied, his focus unwavering.

Isshin lunged at Kazuki, but this time, there was a change in how their blades met. With a deft movement, Kazuki’s newly transformed Zanpakuto caught the fiery trail of Engetsu, the clash producing a shimmering burst of light and dissipating heat.

Taking advantage of Isshin's momentary imbalance, Kazuki activated the Shinsō ability of his Zanpakuto. With a rapid extension, Kamijō Tenseiga thrust toward Isshin. But Isshin managed to evade, a strand of his hair falling as evidence of how close it had been.

"Not bad, kid," Isshin acknowledged.

"I could say the same," Kazuki retorted. He felt the ambient spiritual energy around him, channeling it into his blade. Starlight Requiem was active.

Before Isshin could move, he found his vision clouded by a sudden brightness. It was not blinding but distracting enough. Seizing the opportunity, Kazuki moved in, his blade slashing toward Isshin's side. But Isshin was too experienced to be caught off guard completely; he parried the attack but was pushed back due to the force behind it.

As they squared off again, the tension in the air was palpable. Isshin glanced at the ground and noticed a slight singe where Kazuki had stepped. It appeared that the Starlight Requiem ability had more than just visual effects.

"Interesting," he mumbled to himself. Isshin took a deep breath, gripping Engetsu firmly, ready to change the tempo of the battle.

And so, he attacked, his fiery blade creating arcs of heat and light as he unleashed a series of swings. Kazuki parried, but it was clear that the continual barrage was starting to wear him down. He had to end this soon.