Ichigo Kurosaki vs. Muramasa

 is a battle which occurs during the Zanpakutō Rebellion. It is the final fight in the Rebellion, focusing upon the conflict between Substitute Shinigami Ichigo Kurosaki and the instigator of the Rebellion, Muramasa.

Prelude
As Ichigo is immersed in Muramasa's Reiatsu, he, unconsciously traveling inside the crimson-red Reiatsu, emerges from the water in Kōga Kuchiki's inner world. Wondering where he ended up, he hears Muramasa's footsteps upon the water. Stating he is surprised to see him inside the inner world of his master, the Zanpakutō Spirit asks Ichigo how he managed to reach this place, with Ichigo stating he has no clue either.

When Ichigo asks Muramasa what this place is, Muramasa tells him he used to have an inner world like other Shinigami. As Ichigo realizes where he is, he, protesting, states Muramasa's Shinigami master is dead. Saying it is beyond his comprehension, Muramasa, wondering why he came here, postulates whether this is merely an illusion, or if his reunion with Kōga manifested this place from memory. As he states their time here is short, a pillar plunges into the water below.

Thanking the fates which kept the two of them intertwined, he states it has given him the chance to finish off their previous fight. As his sword materializes in his hand, he appears before Ichigo.

Battle
As the two clash in mid-air, Ichigo questions why they have to fight, as there is no longer any reason to do so. As he pushes Muramasa away, the latter states Ichigo is weak, and his power will nourish his body. Stating he must fight until there is no strength left in his body, he points his sword at Ichigo. As the blade glows a purple hue, he tackles Ichigo into the body of water. As this creates a huge explosion, Muramasa prepares to strike Ichigo with his blade. Stating that will not work, Ichigo deflects Muramasa's strike with a Getsuga Tenshō.

This action forms a typhoon, which Ichigo cuts in half with one swing as he emerges from the water. Appearing behind him, Muramasa raises an outstretched hand towards him. Stating his trickery will not work twice, Ichigo, backing away, tracks the spirit threads through the water's reflection. As he fires a Getsuga Tenshō at Muramasa, who evades the attack, Ichigo is bound in mid-air, held in place by Muramasa's threads.

Appearing once more, Muramasa states Ichigo will never defeat him if his strategy is to blindly swing his sword around. Wondering how Muramasa was able to bind him through his ability, Ichigo, glancing down at the water, notices the multitude of hands binding him. Stating it is all over, Muramasa, materializing his sword, laughs wildly. When a pillar collapses behind him, disrupting the technique, Ichigo fires a Getsuga Tenshō, dispersing the spiritual threads below him.

When Muramasa is surprised at this, Ichigo states the true nature of Muramasa's abilities is disguising his attack in reflections in order to trick his opponent into believing his attack is invisible and unforeseeable. With this in mind, Ichigo, countering this by churning up the water with a Getsuga Tenshō, pushes Muramasa back. Clashing with him, he, charging at a seemingly off-guard Muramasa, runs him through with Zangetsu.

Smiling, Muramasa, fading away from Ichigo's blade, appears behind Ichigo, lightly cutting him on the arm. As Ichigo turns back to face him, the illusion fades away, revealing another figure. He clashes with Muramasa, who explains how he has other abilities, despite his full powers being inaccessible while in Kōga's inner world. Intentionally allowing himself to get pushed back by Ichigo, who runs through him again, Muramasa disappears.

Surprised at this, Ichigo is surrounded by several replicas of Muramasa. As Muramasa explains how Ichigo had fallen within another of his techniques when they began fighting. the figures, charging at Ichigo, overwhelm him. Unable to land a hit on them, he is sent back when the real Muramasa, appearing behind him, knocks him down onto one of the pillars. Panting heavily, Ichigo wonders how he will be able to counter the illusions of Muramasa's Shikai.

Interjecting, Zangetsu, stating his hypnosis abilities do not have any effect upon him, says he can be his eyes, but they will have to utilize the bond between Shinigami and Zanpakutō. Stating he understands what is required of their partnership, Ichigo, closing his eyes, faces off against Muramasa, knocking him into a nearby pillar. Propelling himself off of it, Muramasa, smirking, returns to fight Ichigo, briefly clashing with him.

Using his illusions, Muramasa appears behind Ichigo, who is able to block the strike due to his heightened awareness. Realizing he has seen through his power, the Zanpakutō Spirit sends Ichigo crashing into a pillar, but Ichigo emerges unharmed. Immersing his blade in black Reiatsu as Muramasa charges from behind. Ichigo uses Getsuga Tenshō. sending Muramasa crashing through several pillars.

Heavily damaged by his attack, Muramasa, realizing Ichigo has Zangetsu fighting with him, charges at Ichigo once more, clashing briefly. Repelled, Muramasa, sent hurtling to the ground, stumbles up once more. Stating he finally understands what Zangetsu means, in which a Shinigami and a Zanpakutō must acknowledge the existence of each other, Ichigo asks Muramasa if he understands that simple fact, causing Muramasa to writhe in anger.

As Ichigo starts berating him on his beliefs, the pillar they are standing on crashes into the water. Sliding across the surface of the water, they clash along the way. As Ichigo stops to examine his surroundings, Zangetsu states time is nearly up, for Kōga's inner world is starting to destabilize because of the resent held by the many Hollows he has consumed. Taking Ichigo by surprise, Muramasa emerges from the water behind him.

When they fight briefly, Ichigo forces Muramasa backwards. As Muramasa, having collided with a ruined pillar, emerges from the ruin, he notices the pillar is beginning to collapse on him. As Muramasa falls to the bottom of the ocean alongside the rubble, Ichigo watches on in shock. Beginning his slow descent, Muramasa, contemplating how Kōga's voice never reached him, is resigned to his fate, closing his eyes in reassurance.

As Ichigo calls out to Muramasa, snapping him out of his stupor, Zangetsu tells Ichigo they have to leave unless they want to remain trapped here. Rushing out of the water, Muramasa lands on a nearby pillar. When Ichigo questions his motives behind the Rebellion, Muramasa states it is none of his concern. When Ichigo states his own master refused him, Muramasa explains how Kōga was powerful enough to have ruled over Soul Society, and it was his pride in Kōga's abilities which motivated him. Stating he is still able to fight, Muramasa clashes with Ichigo.

Once again questioning Muramasa's motives, Ichigo says it was he who vowed to free the Zanpakutō from their Shinigami. Amused, Muramasa, revealing he just said that to deceive the Shinigami, charges at him before taking refuge on a nearby pillar. Stating Muramasa even said he was directly responsible for his master's death, and he probably knew Kōga could not care less about his Zanpakutō, Ichigo says despite all this, he still fought to release Kōga from his seal because deep down, he still desired to communicate with his Shinigami master.

Glancing at his hand, Muramasa, noticing it is becoming transparent, realizes his goals were fleeting and could not last forever. As Muramasa moans in pain momentarily, a Hollow hole forms on his chest. As Muramasa, panting heavily, tries to suppress the Hollows, Zangetsu, repeating his warning, states Muramasa's body of Reiatsu could destroy Karakura Town if he turned into a Hollow. Believing Muramasa would never allow himself to permanently become a Hollow, Ichigo asks Muramasa why he made a mockery of the bond between a Shinigami and a Zanpakutō, since he very well knew the strength of this connection.

Ignoring his question, Muramasa states his powers merely allow for a Zanpakutō to assume a material form. Ichigo tells him Zanpakutō are not just tools for destruction, and he did not have to obey his Shinigami master. As a tidal wave consumes Kōga's inner world, a Hollow mask gradually forms upon the face of Muramasa, who realizes he has run out of time. As Zangetsu states they must finish things now, Ichigo releases a burst of Reiatsu.

Tearing off his Hollow mask, Muramasa doing the same. Meanwhile, in Karakura Town, the Shinigami and their Zanpakutō Spirits kill off all of the remaining Hollows. As Muramasa's Reiatsu dome crackles with red energy, Captain Tōshirō Hitsugaya wonders what on earth is happening in there. Charging at each other one final time, Ichigo and Muramasa, clashing, are submerged by a tidal wave. The dome proceeds to dissipate, cracking into pieces, much to the surprise of the external forces.

Aftermath
As Muramasa sinks in the water once again, aIchigo calls out to him repeatedly. He comments upon the ironic nature of their fight, in which Ichigo's voice was able to reach his soul. As he raises his hand out, Ichigo, grabbing it, rescues Muramasa. At the shoreline, as Rukia Kuchiki wonders what transpired inside of the dome, Sode no Shirayuki states the Hollow Reiatsu has disappeared. As Yasutora Sado wonders if Karakura Town will be safe now, they notice Ichigo sitting next to Muramasa on the main island, the Zanpakutō Spirit wondering if this is what it feels like to understand one's soul.

When Ichigo confirms this, Muramasa, blaming himself for Kōga's downfall, coughs out spatters of blood. Reassuring Muramasa, Ichigo states everyone makes mistakes, so they just have to accept that and do what they can. As Rukia and Orihime Inoue come across to the island, Muramasa, falling to the ground, says "I will someday...". As Ichigo tries to hold his hand, Muramasa dematerializes back into a sword, which clatters, broken, to the ground. It disappears into energy, leaving Ichigo surprised.

When he asks the others if they are alright, which they confirm, Orihime asks if Muramasa disappeared. As Ichigo explains how he kept his pride as a Zanpakutō until the very end, Captain Byakuya Kuchiki appears before the three of them as it begins to rain. As the Zanpakutō return to the swords of the Shinigami, Byakuya, stating this is the second time he has thanked him, leaves the area with Shunpo. As Ichigo accepts his thanks, they proceed to leave alongside him.