Kentaro vs. Shinzo

A battle involving Kentaro Hiroshi, fighting on the behalf of Akiye to gain vengeance for her imprisonment and torture sixteen years ago, and Shinzō, battling to regain the Kyūtai stolen previously by Kentaro to slow his rapid ageing, occurred some months prior to the Collapse following the defeat of Oda Kōhai and the return of Averian.

Prelude
Realizing from their last encounter that he could not stand against Shinzō in conventional combat, Kentaro sought ways to limit his power and restrict his abilities, with Kusaka claiming this was his only true hope. Having already robbed him of the Kyūtai he carried but unwilling to bond the legendary orb himself, Kentaro sought out the only two people left alive with any concrete knowledge and experience regarding Shinzō and his powers: Shigeru Yūdai and Garian Shinjo. Recalling that Naibu Shizuka had reported a foreign spiritual power fuelling Shinzō's strength during the rescue of Akiye, Kentaro speculated that understanding this source could perhaps be the key to unravelling Shinzō's power and striking a fatal blow against him, a belief shared by Kenji, who agreed to aid his son on the condition Kentaro only act after thoroughly researching his target. Not wishing to fall into the trap he did last time Kentaro agreed to his father's words.

Travelling to the, Kentaro, alongside his father, visited Garian on the slopes of Monte Rosa in hopes of casting some light on the source of Shinzō's strength. Although he was hesitant to share this information, worrying that Kentaro may someday go down the same dark-path for the sake of power once trodden by Shinzō, Garian eventually revealed what he knew. He explained that Shinzō was one of very few individuals who had successfully forged themselves a piece of Kikai to embed within his own body, and that it was this stone, created from countless sacrificed spiritual beings, that granted Shinzō his god-like power. He admitted to being in-the-dark regarding the removal of Kikai however, stating that Kentaro was on his own in that regard. Armed with this knowledge Kenji set out to follow-up some leads.

Kentaro next sought out Shigeru, who was busy trying to track down his brother, Teruo Yūdai. Although helping Kentaro would cause him to lose the trail Shigeru nevertheless aided his one-time student, revealing to Kentaro that Shinzō was essentially immortal. He detailed the nature of the Shirushi, explaining it housed not only Shinzō's power, but also his conciousness in the event his primary body was somehow destroyed. Using the brand as a medium he would return. When Kentaro pointed out that Shigeru was the only one left with the brand, Shigeru admitted that for Shinzō to truly die, he would have to be killed to. He swore Kentaro to secrecy regarding this fact and extracted a promise: if he should kill Shinzō's main body, he would return to kill him (Shigeru). Kentaro promised he would only do this if he could find no other way.

On his return to Horiwari, Kentaro was intercepted by his father, who, in the interim, had devised a means of forcibly removing and destroying the Kikai from Shinzō's body. When asked how he managed this Kenji admitted that he had to pull in multiple favours from Jiro Kazuki and Ryōta Hachirō, who where the only people Kenji knew would be old enough to know of Kikai, and perhaps its forging process. Kenji explained that the seal he developed would work on-contact with Shinzō, forcing the Kikai from his body, rendering him vulnerable. Kentaro noted they had lucked out to which Kenji agreed, wishing his son luck, stating he knew this to be his fight and his alone. Kentaro extracted a promise from his father not to intervene, even in the event Shinzō prevailed, stating he had to do this himself from now-on.

The morning after Kentaro, meeting up with Riki Nagakura and Jinta Kanō, inquired after their report. Riki snorted, revealing the whereabouts of Shinzō, with Jinta remarking they had taken measures to ensure he was not in Kohai Tochi. Safe in the knowledge he could use his Zanpakutō if needed, Kentaro asked where he was, leading Riki to say he was in the ; specifically Nishiendo. Finding it fitting Kentaro thanked his childhood friends for their help, setting out to battle.

Part I
Arriving in Nishiendo, Kentaro launched a successful ambush against Shinzō, extinguishing his spiritual power using and a  made by his mother. With his first attack Kentaro applied his father's seal, forcing the Kikai from Shinzō's body, which shattered like glass upon Kentaro slashing through it with his Zanpakutō. Shocked and enraged, Shinzō blasted his attacker away with his reiatsu, only then realizing who it was who had attacked him. Kentaro remarked they'd fight as equals.

Resolving to kill Kentaro for stealing his Kyūtai and destroying his Kikai, but also laying waste to the Imawashī, Shinzō releases his Zanpakutō into Shikai. Assaulting Kentaro with a series of vacuum-blades, he begins to overpower his younger opponent, who uses Kidō barriers to stave off the assault. Calling him a fool for returning Shinzō breaks through, only for Kentaro to use Utsusemi, enabling him to plunge his Zanpakutō through Shinzō's back.

Kentaro explains that Shinzō can thank Shigeru, stating Shigeru taught him the move, but also that Shigeru was his godfather. Enraged at the mention of the subordinate who had betrayed him, Shinzō released an omni-directional blast from his body, scoring a direct hit. Coughing blood and stripped of his pre-applied Kidō wards Kentaro struggled to his feet once more, successfully blocking Shinzō's follow-up by casting Dōdōjōshō. Unknowing of the techniques nature Kentaro managed to seize his foe in the grip of his spells bony-hand, seemingly crushing him in its grip.

Shinzo, however, managed to survive, albeit with extensive injuries.

Interruption and Flight
Realizing that things had turned against him and that he had grossly underestimated Kentaro's abilities and preparation, Shinzō called on his army of Soulless to distract the young Shiba clansmen, whilst he retreated. Noting Shinzō's power to be false and declaring the latter as nothing but a coward and a fool, Kentaro, exerting his reiatsu, turned to face the Soulless, intending to finish them swiftly so he could return his attentions to their master.

Despite his best efforts Kentaro was eventually swarmed through sheer numbers. Afflicted with the potent poison lacing the limbs of the Soulless, he came to the conclusion that vistory over Shinzō was possible only if he finished things now, resolving to gain Akiye's vengeance even if it cost him his own life. Casting Dōdōjōshō once more, Kentaro forced the group into a single area, where he swiftly incinerated them using Sōtōzashū.

Part II
Despite feeling the effects of utilizing so many high-levelled techniques in rapid succession, coupled with the poison of the Soulless coursing through his veins, Kentaro pushed on, launching an empowered spell through his Dōdōjōshō. The spell cut through Shinzō's right arm and enabled Kentaro to catch up with him, preventing his escape. Stating he was going to end this right now Kentaro dispelled Dōdōjōshō and drew his Zanpakutō, with Shinzō daring the boy to come.

Shinzō blocked Kentaro's attack, with the latter claiming he had fallen into his trap. Revealing he had switched places with a clone created through use of, Kentaro released his , using his momentary invulnerability to phase through Shinzō's counter and slash through his torso. Before the energy-drain could become a problem Kentaro sealed his Bankai, moving into finish his opponent, who managed to block him yet again and jump back. Before he could do so however Kentaro, pouring the remainder of his spiritual power into one more spell, pierced Shinzō's heart with Byakurai.

With his heart pierced and his right arm lost, Shinzō used his last words to curse Kentaro, declaring he would, at the very least, take him out with him. Releasing his Bankai as a final act of defiance, declaring that Kentaro would die for all he had wrought, Shinzō attempted to draw Kentaro into what would be his corpse, so he could effectively tie Kentaro's fate to his own, killing the young upstart.

Out of energy and effectively crippled by the poison coursing through his veins, Kentaro was left with few options, realizing he could not survive in his current state, even should he release his Bankai. Despite great reluctance Kentaro summoned the great reservoir of energy within that originated from Averian, assuming a new form of Hekigenkai unused up until this point, enabling him to force his damaged body to move.

Armed with a pair of wings and renewed spiritual power, Kentaro outdistanced Shinzō's suicide tactic, fluttering safely above the battlefield. Taking this moment to ridicule Shinzō for his actions, explaining that it was only good karma that he should meet his end like this, Kentaro resolved not to allow Shinzō the choice of his end; he would end it for him. Charging a in the palm of his hand Kentaro destroyed the sphere surrounding Shinzō, releasing the energy, causing a massive explosion that dwarfed the bridge.

Aftermath
Releasing Hekigenkai, Kentaro was overcome with fatigue, falling forward. He was stopped short by his father who expressed not only his surprise at his son's victory, but also how well he fought, declaring he was proud of him. Kentaro weakly replied that he needed to rest, leading Kenji to deliver his son to Horiwari, where Kentaro was treated by his mother. In the course of his recovery he noted that he would visit Garian to finish his training before then confronting the elder regarding Shigeru's Shirushi, remembering his victory would be pointless should Shinzō return through Shigeru's brand.

Behind the scenes

 * This battle mirrored an event in Garian Shinjo's past with some clear differences. Instead of allowing Shinzō to flee, Kentaro slaughtered him instead.