"To seal nearly nine times your original power into a single strike. That did surprise me a little." The eerie white substance wrapping Sōsuke Aizen's body like a cocoon now looked more like a thin layer of fabric. "You are the only one capable of keeping up with my evolution."
"Bankai, Rin'en Bokukō!"
Muten Natsu released his Bankai again, and another fire dragon plunged into his body.
Muten Natsu immediately felt his body sink. Uncontrollable Reiatsu spilled out from within him and shattered the ground beneath his feet.
The eerie white armor writhed and grew like a living thing, covering Muten Natsu's entire body.
"That's it..." Sōsuke Aizen showed no intention of stopping him. "Gain new life through destruction, then break free from the cocoon."
The armor squirmed and warped, linking together as it covered Muten Natsu's body and took on the shape of an egg.
"Show me more surprises..." Sōsuke Aizen's eyes widened slightly. "Muten Natsu."
Crack.
With a crisp sound, cracks appeared across the eerie white eggshell.
Countless fissures crisscrossed, splitting the eerie white substance into fragments that fell away, revealing the hollow space hidden within.
There was nothing inside.
No.
Whatever had been inside had already come out.
Bang!
Sōsuke Aizen shifted half a step to the side. Where he had stood, an eerie white claw slammed down hard, then swept sideways toward Sōsuke Aizen's chest.
Sōsuke Aizen drifted back lightly, avoiding the attack with the smallest possible movement.
Blackness surged. Thick Spirit Ink sprayed from the claw's wrist and condensed into an arm blade, gleaming like metal.
Sōsuke Aizen raised his sword to block. Only then did the blurred figure gradually become clear.
Judging by the Reiatsu, it was unquestionably Muten Natsu.
But he no longer looked like Muten Natsu at all.
Or rather... he had lost his human shape.
Like an eerie white tiger crouched on all fours, the savage beast's shoulders, back, and arms were covered in layered armor of exaggerated thickness, with black mist surging through the gaps.
Both hands were also covered in eerie white and had become sharp claws. Black arm blades extended from his wrists, his legs had a beast-like reverse-jointed structure, and a long tail swayed behind him, trailing faint black mist from its tip.
Karmic flames burned quietly over the skull-like mask. The flickering fire formed the translucent shape of a beast's head, hideous and ferocious.
"Is this all?" Sōsuke Aizen swung his blade and forced Muten Natsu back. "This is wrong, Muten Natsu. A Shinigami's Hollowfication is only a method of breaking limits. To complete evolution, you must go even further."
What answered him was a savage roar, followed by a charge even fiercer than before.
"When a person achieves growth, they fall under the illusion that others can do the same thing." Sōsuke Aizen evaded Muten Natsu's attacks with ease. "I expected too much of you... That was my mistake."
The ground was torn apart by claws, then carved open by arm blades.
"You used the Reishi I shed during my evolution to gain a temporary increase. With that, you absorbed even more Reishi and obtained greater power, completing in a short time the transformation that took me far longer to accomplish." Sōsuke Aizen stood in the air, looking down at Muten Natsu from above. "You have not caught up to my evolution. You are merely following behind me, relying on the cocoon I cast off to gain a small improvement. Like a moon that gives off no light of its own, only reflecting the radiance of the sun."
"But no matter how bright the moon is, it cannot bring daylight like the blazing sun." Sōsuke Aizen swung his sword and dove downward. "And when the sun truly approaches the moon... this is what happens."
Before the Zanpakutō even struck Muten Natsu, the powerful Reiatsu contained within it made the eerie white armor on his body crack under the strain.
The heavy armor could not withstand Sōsuke Aizen's attack at all. Fine cracks appeared across it, making Muten Natsu's armor look unbearably fragile, as if it would fall apart in the next moment.
And yet...
Boom!
Rolling black mist burst from the cracks, then detonated violently. The terrifying force sent Sōsuke Aizen flying.
"Roar!"
Muten Natsu threw his head back and roared. Rin'en Bokukō surged from the Spirit Ink, turned into a black fire dragon, and crashed into his body.
The already solidified eerie white armor grew even further. His claws lengthened, serrations appeared along his arm blades, and spikes rose from the armor on his back.
Pitch-black Spirit Ink traced wailing demons across the eerie white armor. Cold karmic flames danced at his elbows and the tip of his tail, while faint black mist spilled from his shoulders and linked together behind his head, forming flowing ribbons.
Muten Natsu swung his long tail. The karmic flames at its tip condensed and aimed toward Sōsuke Aizen.
In the next instant, unrestrained black fire exploded, and a burning path of karmic flame stretched outward, destroying everything it touched.
"A Hollow's body is unstable to begin with, and now it's being burned by karmic flames..." Sōsuke Aizen's figure flickered as he closed in within an instant. "Fireworks may be dazzling, but they are nothing more than a fleeting flash."
Just as Sōsuke Aizen's attack drew near, ink spread beside Muten Natsu, then exploded.
Bursting black fire churned through the shockwave, leaving a massive, horrifying crater in the ground.
Sōsuke Aizen pulled back. Muten Natsu's body now contained far too much unstable power. He was a massive powder keg.
In a sense, this was no longer a battle. It was a race.
Either Muten Natsu would be burned away by the karmic flames, or before that happened, he would catch Sōsuke Aizen and drag him into the explosion with him.
Muten Natsu bent his limbs. The ground beneath him shattered, and his monstrous body became a blur as he charged at Sōsuke Aizen.
Almost the moment Sōsuke Aizen dodged, black fire exploded beside Muten Natsu. The shockwave forced his body to change direction, accelerating him even further toward Sōsuke Aizen.
In an instant, several Sōsuke Aizens appeared in the air at once, and several clusters of black fire exploded along with them.
The deafening roar overlapped with the crash of colliding shockwaves. The distance between them grew shorter and shorter.
At last, the eerie white claw touched Sōsuke Aizen's body. Karmic flames exploded behind Muten Natsu, driving both of them down into the ground.
Black mist surged wildly, swelling into a sphere. Then karmic flames detonated and shot into the sky.
A terrifying shockwave crushed the ground as it spread in every direction. Even far away, where the blast had not yet reached, entire stretches of buildings shook from the trembling earth.
Almost every gaze was drawn to that horrifying explosion.
At the center of the blast, a pair of pure white wings slowly unfurled in the shape of butterfly wings.
"I have already come to understand this kind of attack as well." Sōsuke Aizen spread his wings and looked at Muten Natsu, who was right in front of him. "But you, having lost your self-awareness, can no longer understand anything."
"In your eyes..." Muten Natsu's voice was layered with a savage roar. "Have I already lost all reason?"