Chapter Summaries

Muzan learned how soul power strengthened successors and began hunting them to develop his own soul, while Oboro sensed his evolution and prepared to confront him as his life dwindled. Muzan attacked Ayamiko’s rebel stronghold and provoked her by insulting Oboro, setting their battle in motion.

• Muzan ordered Kokushibo and two others to search for Oboro, deciding that finding Gyutaro would be the best approach.
• Muzan realized that soul power amplified successors’ minds and Blood Demon Arts, and planned to hunt them to temper his soul and possibly devour Oboro’s.
• A month later, Oboro sensed Muzan’s progress and a successor’s death, then resolved to seek Muzan before his remaining vitality ran out.
• Muzan entered Ayamiko’s stronghold, killing hostile demons and rendering humans unconscious as he walked through the defenders.
• Ayamiko confronted Muzan and revealed her powerful Blood Demon Art, while Muzan called her Oboro’s toy and warned that she would die.

Muzan defeated and consumed Ayamiko, an inheritor whose Blood Demon Art let her teleport across marked ground. By using the power of the soul, he trapped her and grew stronger, then sensed Oboro nearby and continued toward him.

• Muzan dismissed Ayamiko’s beliefs, and she attacked him by teleporting behind him and enlarging her arm.
• Muzan blocked Ayamiko’s strike with a wall of flesh and expanded it into a cocoon that suppressed her Blood Demon Art.
• Muzan immobilized Ayamiko with an enormous eye and flesh tendrils, then crushed and swallowed her.
• Muzan explained that the power of the soul let him overcome the inheritors’ soul-based pressure and grow stronger as he reclaimed them.
• Oboro sensed another inheritor’s death, smiled, and continued walking toward Muzan.

Akaza fought Gyutaro and Daki while Kokushibo and Doma watched from hiding instead of helping. As the battle continued, Doma questioned Kokushibo about whether Muzan could defeat Oboro.

• Akaza confronted Gyutaro and Daki alone, furious that Kokushibo and Doma were watching instead of joining the fight.
• Gyutaro kept Akaza at range with Flying Blood Sickles, while Daki’s sashes disrupted Akaza’s attempts to close in.
• Akaza recognized that Gyutaro’s skilled movement and footwork let him evade Destructive Death: Compass Needle and counter Akaza’s attacks.
• Gyutaro and Akaza exchanged another barrage of blood blades and fist strikes as the fight continued.
• Doma told Kokushibo that Gyutaro’s strength matched what they knew about Oboro, then asked who would win if Muzan faced Oboro.

Doma and Kokushibo turned against Muzan and sought Oboro, while Akaza was ambushed and beheaded by Kokushibo. Oboro, unable to find Muzan, met the two defectors on the road and learned they had come to join him.

• Doma interrupted Akaza’s fight with Gyutaro, froze Akaza, and helped Gyutaro’s slashes leave him badly wounded.
• Akaza fled the battlefield, but Kokushibo ambushed him, severed his head, and refused to explain why.
• Oboro found an inheritors’ stronghold already destroyed and decided to wait at another inheritor’s territory for Muzan.
• Doma and Kokushibo appeared before Oboro and addressed him as their lord.
• Oboro realized the two Upper Ranks had defected and remarked that Muzan was likely furious.

Oboro accepted Doma and Kokushibo’s request to become Successors, and Muzan confronted the two traitors in the Infinity Castle. Doma and Kokushibo resisted Muzan’s power, and Oboro appeared beside him, ending with Muzan facing the question of whether he would flee.

• Oboro learned that Doma and Kokushibo had betrayed Muzan and agreed to grant their wish to become Successors.
• Muzan summoned Doma and Kokushibo to the Infinity Castle and ordered the new Upper Rank Six to kill them.
• Muzan killed Doma, but Doma regenerated and revealed that he and Kokushibo had gained a power like Muzan’s.
• Muzan unleashed his spiritual pressure, but Doma and Kokushibo were unaffected.
• Oboro appeared beside Muzan inside the Infinity Castle and asked whether he was going to run.

Oboro revealed the overwhelming power of his soul to Muzan, who realized his own soul-based evolution could not match it. Oboro explained how Muzan and other forces fit into his plan to spread Breathing, soul power, and combat arts throughout the world, leaving the larger arrangement in place to develop over time.

• Muzan halted his retreat and raised walls of flesh and bone spikes to attack Oboro.
• Oboro exposed his soul, terrifying Muzan with the vast difference between their powers.
• Oboro praised Muzan's independent research into soul power and recognized that Muzan had developed abilities beyond ordinary Blood Demon Arts.
• Oboro recalled that Muzan had passed fragments of his soul to Doma and Kokushibo, making Muzan the vessel through which soul power could spread among demons.
• Oboro explained that the Demon Slayer Corps, Muzan, and Gyutaro represented Breathing, soul power, and combat arts in his plan to raise the world's power level.
• Oboro concluded that the larger plan was set and that its spread would now depend on time.

Oboro killed Nakime and left Muzan unable to hide from his soul-sensing power or escape through Infinity Castle. As Muzan took shelter from the rising sun, Oboro appeared at the temple entrance and told him he could no longer escape.

• Nakime used her Blood Demon Art to transfer Muzan, Kokushibo, and Doma out of Infinity Castle, but Oboro followed her through soul marks he had placed on Doma and Kokushibo.
• Oboro appeared behind Nakime and killed her before she could transfer him again.
• Muzan escaped into the real world, realized Oboro could track his soul and move through space, and fled to stay ahead of him.
• Near dawn, Muzan hid in a ruined mountain temple and worried over Oboro's powers as the lingering shock blurred his vision.
• Oboro appeared at the temple entrance and told Muzan that he could no longer escape.

Oboro confronted Muzan and used his soul power to take Muzan’s vital blood, restoring his youth and achieving the sunlight immunity Muzan had long sought. He left Muzan alive and set him on a path toward a future struggle with Kokushibo, Doma, and their successors, while Muzan suspected Oboro came from another world.

• Oboro entered Muzan’s room as Muzan transformed the surroundings and created malformed monsters to attack him.
• Oboro unleashed his soul pressure, froze Muzan and the monsters, and warned Muzan that Doma and Kokushibo could develop soul power and eventually challenge him.
• Oboro took a portion of Muzan’s vital blood, which restored his youthful appearance and revealed that he had achieved eternal life without fear of sunlight.
• Oboro told Muzan he might fulfill his wish if Muzan survived the coming conflict, then walked into the dawn unharmed.
• Muzan realized Oboro had manipulated him and the Demon Slayer Corps, and concluded that Oboro came from an unfamiliar space beyond the world he knew.

Oboro reflected on his new Demon King body and settled into a quiet life near Mount Kumotori as the world changed around him. When he visited the Kamado Clan’s home, Kamado Tanjuro recognized that Oboro was not the figure he appeared to be.

• Oboro judged that his sunlight-resistant body was powerful in Demon Slayer’s world but vulnerable to stronger worlds and abilities.
• Oboro sensed that the Demon Slayer world’s will had recovered and was nearing its final growth, while he could do nothing more to help it.
• After years passed, Oboro changed identities, settled in the town below Mount Kumotori, and bought a residence.
• Oboro visited the Kamado Clan’s home and met Kamado Tanjuro, who recognized his black haori as a family heirloom linked to Oboro.
• Kamado Tanjuro suddenly raised his woodcutting knife and declared that Oboro was not the lord from the family’s stories; Oboro praised his recognition.

Oboro met Kamado Tanjuro, who recognized the demonic origin beneath his human appearance but accepted him while keeping him outside for his wife's safety. After learning how the Kamado Clan had developed its own method of circulating qi, Oboro left Mount Kumotori and reflected on how his bond with Tanyilang had led to the boy's early death.

• Tanjuro sensed the demon's corruption in Oboro and recognized him as the person from his memories, while Eri shut herself inside the house.
• Oboro explained that he had become a new life-form by overcoming sunlight, and Tanjuro accepted his identity but declined to invite him inside.
• Oboro and Tanjuro spoke outside about the Kamado Clan's history, and Oboro learned that the clan had developed its own method of circulating qi.
• Oboro realized that Tanyilang and later generations had pursued breath cultivation because of their bond with him, and that their experiments may have caused early deaths.
• As he descended Mount Kumotori, Oboro regretted the harm his influence had caused and wondered whether his feelings were an aftereffect of leaving Hunter x Hunter.

Tanjiro Kamado carried on the Kamado family traditions while Oboro watched the world’s growing conflict from Mount Kumotori. Doma, Kokushibo, Gyutaro, Muzan, and the Demon Slayer Corps drove a surge in demons and the spread of new powers, as Sakonji Urokodaki and Jigoro Kuwajima appeared.

• Tanjiro Kamado preserved Blue Spider Lilies, brought Oboro wild vegetables, and carved him a new wooden cane.
• Doma and Kokushibo secretly turned people into demons, disrupting Muzan’s efforts to control his forces and hunt inheritors.
• Doma revived his faith under a new guise, freed demons from Muzan’s blood curse, and spread the power of souls.
• Kokushibo likely slaughtered the reshuffled Twelve Kizuki, while Gyutaro and Daki attacked demons, inheritors, and Demon Slayer Corps members alike.
• The Demon Slayer Corps expanded with official support, and the Ubuyashiki Clan helped spread Breathing Styles and training.
• Sakonji Urokodaki and Jigoro Kuwajima appeared as new figures in the changing world.

Oboro assessed how the Demon Slayer world had changed and reviewed the seeds of power he had planted there. The Demon Slayer Corps and Kamado Tanjuro had developed new forms of qi cultivation, but Oboro remained worried about surviving the will of the next world.

• Oboro noted that Muzan’s demons, the Demon Slayer Corps, and human society had become widely known and closely monitored, reshaping the world beyond its original course.
• Oboro judged that soul power and Gyutaro’s martial arts had helped the world develop but had failed to produce the advanced techniques he sought.
• Kamado Tanjuro developed Qi Acupoints, while the Demon Slayer Corps created Qi Vortices from breathing exercises.
• Oboro’s system combined the two methods with his Earth memories to create qi refinement and a Dantian Qi Sea cultivation method.
• Oboro concluded that his soul and system would be his most important defenses if the next world’s will tried to erase him.

Oboro continued cultivating qi while preparing to witness the final battle between Muzan, Kokushibo, and Doma in Ueno. As his journey in the Demon Slayer world neared its end, he reflected on how the world had changed his understanding of inheritance and miracles.

• Doma visited Oboro and told him that he and Kokushibo would fight Muzan in Ueno in ten days.
• Doma asked Oboro to make him his only successor if he survived, but Oboro told him to survive first.
• Oboro planned to attend the battle, believing Muzan, Kokushibo, and Doma would follow the course he had arranged.
• Oboro reflected that his experiences in Demon Slayer had deepened his understanding of inheritance, though he felt the will of inheritance did not suit him.
• Oboro concluded that a supreme will carried to its utmost could connect to miracles, a power capable of overturning everything.

Oboro said farewell to the Kamado family on Mount Kumotori and left for home, ending his ties to their clan. Days later, the new Twelve Kizuki gathered outside Ueno to ambush Kokushibo, who realized Muzan had sent them as weapons.

• Oboro told Kamado Tanjuro he was leaving and said the Kamado Clan no longer needed to bear his karma.
• Oboro confessed that he had originally intended to use the Kamado Clan, but Tanjuro understood their bond had been sincere despite his motives.
• Young Tanjuro asked whether Oboro had a family, and his grandfather assured him Oboro would return to them.
• The new Twelve Kizuki arrived at the agreed battlefield outside Ueno, where Kokushibo was waiting alone.
• Kokushibo recognized that Muzan had sent the Twelve Kizuki to surround and kill him and suspected Muzan was hiding nearby.

Doma arrived to join Kokushibo and defeated the Twelve Kizuki sent to kill them, revealing how powerful his soul technique had become. As Doma welcomed the approaching familiar auras, the confrontation with Muzan’s side was about to grow more crowded.

• Doma appeared beside Kokushibo and taunted the Twelve Kizuki, prompting Upper Rank Three to attack him.
• Upper Rank Three marked Doma’s soul with his Blood Demon Art, but Doma redirected the damage into a miniature Bodhisattva made from another soul.
• Doma unleashed a blizzard that killed the remaining Twelve Kizuki and froze them into works of art.
• Kokushibo recognized Doma’s soul technique, Separation, which let him control the souls of creatures he had devoured.
• Doma and Kokushibo sensed several familiar auras approaching, and Doma welcomed the coming excitement.

Doma and Kokushibo gathered with several inheritors as they waited for Muzan, while Daki and Gyutaro arrived seeking revenge on the former Upper Ranks. Gyutaro appeared to defend his sister and promised to grant her wish to kill Doma.

• Several inheritors confronted Doma and Kokushibo, suspecting Doma had revealed Muzan's whereabouts and debating the gathering's purpose.
• Doma explained that the battle had the tacit approval of a mysterious Lord and served as a test for everyone involved.
• Daki arrived and vowed that she and Gyutaro would not let Doma and Kokushibo escape again.
• Gyutaro emerged from Daki, comforted her, and agreed to leave Doma alive so she could kill him herself.

Oboro gathered the inheritors and Muzan’s former allies in the Infinity Castle and declared that they would settle the era through battle. Muzan isolated Doma to begin killing the traitor, while the others were sent to fight elsewhere.

• Doma warned Gyutaro that Daki was in danger, then he and Kokushibo entered the Infinity Castle as its passages opened.
• Oboro summoned the inheritors, and everyone bowed to him when they arrived on separate floating platforms before Muzan.
• Oboro explained that the inheritors were to kill Muzan, while Daki and Gyutaro were to kill Doma and Kokushibo, and said he would not interfere.
• Muzan reminded Oboro of their agreement that victory would earn him freedom from Oboro’s interference and help becoming a perfect life-form.
• Muzan used the Infinity Castle to separate the fighters, left Doma alone with him, and swallowed Doma inside a rapidly expanding mass of flesh.

Muzan used his Soul Spores to attack Doma throughout the Infinity Castle, but Doma disrupted Muzan’s control and escaped the fatal assault. Doma then unleashed his Water Lily Bodhisattva against Muzan.

• Muzan transformed the Infinity Castle’s platforms into flesh constructs and attacked Doma with bone spears and toxic blood mist.
• Muzan’s clone struck Doma from behind, while Muzan’s cells began growing inside Doma’s body.
• Doma used his soul ability to disrupt Muzan’s mental control, then stopped breathing and digested the cells inside him.
• Muzan tore apart Doma’s clone, which turned out to be ice, as snow spread through the castle.
• Doma manifested a colossal Water Lily Bodhisattva and ice Snow Princesses that attacked Muzan with frozen mist.

Muzan fought Doma and Kokushibo while trying to control Infinity Castle and attack the scattered inheritors. Kokushibo’s concealed soul ability let him ambush Muzan, while Doma secretly used the chaos to feed on inheritors and recover.

• Muzan destroyed Doma’s Blood Demon Art, but Doma’s soul ability injured him and left him open to Kokushibo’s attack.
• Kokushibo struck Muzan with his demon blade, injuring his soul and forcing him to endure the pain while fighting back.
• Muzan’s flesh attacks trapped and killed some inheritors as he divided his attention between the battle and Infinity Castle.
• Kokushibo used his concealed presence and knowledge of Infinity Castle to repeatedly ambush Muzan, keeping him under pressure.
• Oboro noticed that Doma was consuming inheritors as blood packs to restore his strength.

Gyutaro and Daki fought Doma, who wanted Gyutaro’s black haori and the chance to become Oboro’s sole successor. Gyutaro severed Doma’s head, but Doma regenerated, and the battle continued with Doma discovering he had been poisoned.

• Doma told Gyutaro he hated him and mocked him for failing to wipe out the demons despite receiving Oboro’s favor.
• Gyutaro and Daki fused through their Mutual Symbiosis ability and attacked Doma with blood blades and sashes.
• Doma blocked Gyutaro’s attack with ice, then used soul puppets to inflict mental pain on the siblings, especially Daki.
• Gyutaro used his speed to cut off Doma’s head, but Doma regenerated from it before it hit the ground.
• Doma’s headless body exploded into ice spikes, forcing Gyutaro to leap back and causing his black haori to fall away.
• Gyutaro told Doma that his strike had already cut him, and Doma realized he had been poisoned.