Ichigo Kurosaki vs. Yhwach: Final Fight is a conflict which takes place during the Quincy Blood War. It focuses on Ichigo Kurosaki's final fight with the Emperor of the Wandenreich and the usurper of the Soul King's power, Yhwach.
After breaking Ichigo's Bankai and revealing that The Almighty allows him to both see and transform the future, Yhwach completely overpowers Ichigo, who loses all hope of winning as he realizes that neither his sword nor Orihime Inoue's powers have any effect on Yhwach. Seeing this, Yhwach expresses his disappointment before declaring that it is time for Ichigo to return the power that Yhwach gave to him as he proceeds to absorb Ichigo's Hollow and Quincy powers. With his merged Hollow form dissipating, Ichigo falls to the ground, barely conscious, while Yhwach laughs maniacally as darkness swells behind him.
Yhwach proceeds to initiate a third Auswählen, which lethally incapacitates Jugram Haschwalth and kills Gerard Valkyrie while draining power from both of them, before opening a portal as he bids Ichigo farewell while promising to bring ruin to all of existence. When Rukia Kuchiki and Renji Abarai appear, Yhwach decides to leave the portal open so they can pursue him and be rewarded with death in their happiest moments if they wish. As he promises Rukia and Renji that they will feel the looming shadow of death for all eternity, Yhwach steps into the portal.
Angered by Yhwach's words, Renji attempts to attack Yhwach with Zabimaru, only for Yhwach to effortlessly rip apart the Zanpakutō as he disappears into the portal. As she tends to a wounded Orihime, Rukia is shocked to learn that Yhwach possess the power to rewrite the future and wonders how anyone could stand against such an ability.
Orihime apologizes to Ichigo for being unable to fix Tensa Zangetsu, prompting Rukia to note that even the power of rejection cannot repair something that has been broken in all possible futures. Suddenly, Renji hoists Ichigo up and declares that he is going to pursue Yhwach while dismissing Rukia's plea for him to wait until they have a plan, prompting Ichigo to state that it is all over. However, everyone is shocked when Ichigo is suddenly stabbed in the shoulder by Shūkurō Tsukishima with his Book of the End, which prompts Ichigo to demand to know what he is doing. When Tsukishima claims that an approaching Kūgo Ginjō instructed him to ally himself with Ichigo, Kūgo states that he only intends to repay the debts that they owe to Ichigo.
Telling Orihime to use her Sōten Kisshun on Tensa Zangetsu once more, Tsukishima explains how she should be able to reject its broken state even if the future has been overwritten if he inserts a past where it was not broken as Tensa Zangetsu is fully restored. As Tsukishima notes that this settles all debts between him and the Fullbringers, Ichigo stands up with his Bankai in hand and his confidence completely restored before confirming this. Meanwhile, in the Seireitei, Yhwach emerges from his portal and is greeted by Sōsuke Aizen, who admits his surprise at encountering Yhwach in Soul Society once more before welcoming Yhwach to his Soul Society.
Within the portal, as Ichigo and Renji run along a path of condensed Reishi, Ichigo suddenly collapses, prompting Renji to ask him if he is alright before slinging Ichigo's arm over his shoulders in order to carry him along. When Ichigo questions him coming along despite his injuries, an irritated Renji headbutts and punches him before noting that he and Rukia were separated by a great distance for many decades. Reminding Ichigo that he brought them back together, Renji states that he decided to carry Ichigo onward whenever the latter felt unable to go on and claims that he will do so until the day Ichigo dies before telling him to never say Renji should stay behind again because he does not intend to tell this story again, prompting Ichigo to smile.
Back in the Seireitei, an enormous blast of Yhwach's Reiatsu surges through multiple buildings as Aizen, his restraints having been destroyed by the blast, admits that he thought Yhwach would finish his battle in the Royal Realm without coming down to Soul Society before noting that he must have had some trouble with Ichigo, only for Yhwach to point out how Aizen was the one whom Ichigo defeated. Thanking Yhwach for destroying his chair, Aizen proclaims that he can now stand in his way before claiming that he has only ever desired to crush all who would control him. Suddenly, Ichigo and Renji seemingly appear behind and attack Yhwach, who repels them before claiming to have already foreseen this occurring. When Tensa Zangetsu gains a large crack in the blade, Yhwach admits that he was trying to destroy it completely before noting that Ichigo possesses truly accursed luck.
Attacking Ichigo with a blast of Reiatsu, Yhwach wonders if he did not have time for Orihime to heal his wounds before claiming that Ichigo cannot hope to change anything no matter when he arrives. When Yhwach states that the same holds true for him, Renji leaps into the air while activating his Bankai, Sōō Zabimaru, only for Yhwach to cut off his left arm while declaring that he has already crushed all Bankai in the future before deciding to crush Renji himself. Suddenly, Aizen intervenes with Kyōka Suigetsu in hand, prompting Yhwach to mock him for joining forces with Ichigo and Renji in order to defeat him as those he detests would, only for Aizen to use Hadō #99. Goryūtenmetsu in response.
As an enormous energy dragon ruptures the ground and rises above him, Yhwach merely points out that Kyōka Suigetsu has already been broken before blasting Aizen away with one hand. Seeing Ichigo attacking him from behind with a missing arm, Yhwach states that he has already foreseen this as well before stopping Tensa Zangetsu with his hand as he commends Ichigo for allying himself with Aizen. Proclaiming that Kyōka Suigetsu cannot match his power, Yhwach shatters Tensa Zangetsu and blows a hole in Ichigo's torso while declaring that it is over. Yhwach prepares to destroy Ichigo and Soul Society with his Reiatsu, but suddenly finds his hand embedded in Aizen's torso as Aizen notes that Yhwach saw him as Ichigo. Suddenly, the real Ichigo impales Yhwach from behind with Tensa Zangetsu before unleashing a Getsuga Tenshō that rips Yhwach in half.
Staring at Ichigo up-close, Yhwach dissolves into a puddle of Reiatsu as Aizen commends Ichigo for adjusting to Kyōka Suigetsu so quickly. When Ichigo notes that he felt an uneasiness similar to when Aizen placed his allies under the influence of Kyōka Suigetsu on his way to the Seireitei, Aizen explains how he released Kyōka Suigetsu before Ichigo arrived and confirmed that it could affect even Yhwach with The Almighty before stating that only Ichigo remained as the sole person whom Kyōka Suigetsu would not affect. As he notes how useful not showing Ichigo the release of Kyōka Suigetsu proved to be, Aizen is suddenly engulfed by a mass of black Reiatsu, which spreads over the surrounding area as Yhwach, having been revived, notes that Kyōka Suigetsu has been activated before asking Ichigo if he truly believed he had killed him with that attack.
As Yhwach proclaims that his ability to change the future allows him to overwrite even his own death, Ichigo attempts to attack him, only for Yhwach to blast Tensa Zangetsu away before engulfing Ichigo in his black Reiatsu. With his Reiatsu spreading to cover even the Shakonmaku, Yhwach declares that both the Human World and Soul Society will become one before his power, only to be interrupted when Uryū Ishida fires an arrowhead of Still Silver through his chest while recalling his father's explanation of how Still Silver will briefly stop Yhwach's powers upon making contact with his blood. With Yhwach's Reiatsu receding, Ichigo grabs Tensa Zangetsu and leaps toward him on Uryū's command. As Ichigo swings Tensa Zangetsu toward him, Yhwach attempts to break the blade once more, but the white portion of the Bankai crumbles to reveal Ichigo's original Shikai within. Realizing that the dream which Jugram Haschwalth sent him was actually a vision of this future, Yhwach is bifurcated by Ichigo.
With his body dispersing, Yhwach grabs Ichigo's blade and declares that the path to a world with no fear is being closed. Explaining how he had planned to combine Soul Society, the Human World, and Hueco Mundo into one plane of existence where people no longer had to fear death because it and life would be one and the same, Yhwach proclaims that Ichigo's efforts will result in life and death never losing their current forms and all beings living in fear of death for eternity before finally dying.