Chapter Summaries

Xia Xi entered Kurumaji’s inner world and spent a peaceful summer evening with Kurumaji Fuyuka, his long-dead little sister. After promising to live a long life and defeat every demon, he returned to the others having mastered his third Supreme Territory, Thoughts Without Form.

• Xia Xi realized the girl in Kurumaji’s inner world was his little sister, Kurumaji Fuyuka, though he initially misremembered her name.
• Fuyuka told Xia Xi she wanted only to spend time with him, and they sat together on the veranda watching the sunset and stars.
• Fuyuka asked Xia Xi to live healthily and reach a hundred, including the years their parents and she had lost.
• Xia Xi promised Fuyuka he would live to a hundred and kill every demon, including the Demon King, before she disappeared.
• Xia Xi returned to Tamayo, Yushiro, and Sanemi and announced that he had mastered his third Supreme Territory, Thoughts Without Form.

Xia Xi demonstrated his newly unlocked Supreme Territory, [Thoughts Without Form], which resisted Tamayo and Yushiro’s Blood Demon Arts. As Hajimi asked Xia Xi to teach him the move, Xia Xi remained unaware that his Hierophant icon had changed from reversed to upright.

• Xia Xi revealed [Domain Expansion] and called its manifestation [Silent Self-Illuminating Court], while Sanemi Shinazugawa and the others watched in confusion.
• Xia Xi asked Yushiro to attack him with his Blood Demon Art, and Yushiro found that his powers could not affect Xia Xi.
• Tamayo joined Yushiro’s attack with [Bewitching Blood: Fragrance of Visual Illusions], but Xia Xi remained unaffected as rainbow-colored ripples resisted the supernatural energy.
• Xia Xi explained that his true skill was [Thoughts Without Form], which could interfere with Blood Demon Arts, defend against damage, and convert some damage into stamina.
• Xia Xi’s icon quietly changed from [Reversed: The Hierophant] to [Upright: The Hierophant], and Hajimi asked him to teach the move.

Xia Xi tested his newly awakened Supreme Territory with Hajimi and explained how its different forms affected attacks, perception, and defense. As he and Tamayo considered whether Muzan’s Blood Demon Arts were another kind of miracle, Enko Onizuka arrived with an urgent letter: the Tokito Family had encountered a demon.

• Xia Xi had Hajimi punch him to test his Supreme Territory, and the barrier absorbed much of the force while making Hajimi hurt his hand.
• Xia Xi explained the abilities of his red, green, and purple Supreme Territory forms and how his Wall of the Heart resisted Blood Demon Arts and physical attacks.
• Xia Xi and Tamayo discussed whether Muzan Kibutsuji’s Blood Demon Arts were a separate miracle born from his will and obsession with survival.
• Yushiro noticed someone at the courtyard entrance, and Enko Onizuka rushed in with a sweat-soaked letter reporting that the Tokito Family had encountered a demon.

A bear-hunting squad killed a small brown bear, only to be attacked by a powerful blond Demon hiding in the mountains. Kiseki Tokito heard the gunfire and cries for help and rushed to confront the Demon, while his family prepared to defend their home.

• The bear-hunting squad tracked a bear to its den and killed it, but the lead hunter realized it was too small to account for the attacks on the tailor's family.
• The lead hunter sensed danger and urged the hunters to leave the carcass, but a short, blond man appeared and revealed that they had been searching for him.
• The blond Demon tore off one hunter's arm and killed him with a Blue Orb as the other hunters raised their weapons.
• Kiseki Tokito heard gunshots through Moon Breathing, took his Nichirin Blade, and hurried into the forest after telling Yuichiro to protect the family.
• Kiseki Tokito recognized the attacker as a Demon and raced toward the cries for help; one of the Ninja Cats left its post and headed for town.
• Yuichiro and Muichiro armed themselves and stood ready to protect Mrs. Tokito as they hoped Kiseki would return safely.

Kiseki Tokito confronted a blond demon that had slaughtered a hunting party and protected the wounded hunter Boqi. Tokito revealed his swordsmanship and fought the demon in the forest, leaving the battle unresolved.

• Kiseki Tokito met the bloodied hunter Boqi, who warned him that a demon had killed the hunting party and urged him to flee.
• The blond demon appeared and attacked Boqi with a blue energy sphere, but Kiseki deflected it with his Nichirin Blade.
• Kiseki questioned the demon about eating people and warned him not to cross the line he had cut in the earth.
• The demon crossed the line, dodged Kiseki’s slash, and closed in despite being struck by the blade.
• Kiseki used Moon Breathing to fight the demon at close range while Boqi watched, unable to find a clear shot.

Kiseki Tokito fought Shunko while trying to keep the demon away from his family, but Shunko reached the cottage and attacked Yuichiro, Muichiro, and their mother. Seeing his sons hurt, Kiseki unleashed a powerful sequence of Moon Breathing forms and overwhelmed the demon, while Muichiro declared that their father had the same talent as their ancestor.

• Kiseki Tokito used Moon Breathing against Shunko, but Shunko exploited his inexperience and blasted him into a tree.
• Shunko realized Kiseki had been drawing him away from the cottage and rushed toward the Tokito family home.
• Shunko broke into the cottage, where Muichiro wounded his leg with a kitchen knife and Yuichiro cut his arm with a Nichirin Blade.
• Shunko kicked Muichiro aside and slashed Yuichiro's face, but Yuichiro kept fighting to protect his brother and mother.
• Kiseki arrived, saw his sons injured, and unleashed a furious series of Moon Breathing attacks that overwhelmed Shunko.
• Muichiro staggered out of the wrecked room and told Yuichiro that Father had the same extraordinary swordsmanship talent as their ancestor.

Xia Xi treated Kiseki Tokito and his sons after Kiseki killed a demon, then asked Kiseki to join the Demon Slayer Corps. Kiseki accepted with his family’s support, and Xia Xi told them to prepare to move.

• Xia Xi arrived and treated the injured Muichiro and Yuichiro, learning that Kiseki had killed the demon that attacked the town.
• Xia Xi saw that Kiseki’s combat ability had grown dramatically and explained that demons would keep appearing while Muzan lived.
• Kiseki’s wife and sons encouraged him to follow his wishes, and he agreed to join the Demon Slayer Corps so he could protect others.
• Xia Xi summoned a Ninja Cat to inform the Corps that the Tokito Family had agreed to join.
• Xia Xi explained that Kiseki would take the upcoming Final Selection and receive his rank and equipment afterward.
• Xia Xi told Kiseki and his family to get ready to move, leaving them surprised.

Xia Xi warned the Tokito family that Kokushibo might target them, then demonstrated his power and helped them relocate to Tokyo. More than a month later, Tamayo produced the first generation of an injectable drug designed to suppress the Demon Slayer Mark pathogen, and large-scale testing on laboratory mice began.

• Xia Xi explained that Kokushibo could learn about the Tokitos’ Moon Breathing and urged Kiseki Tokito’s family to move before the demon found them.
• To answer Yuichiro’s doubts about the Twelve Kizuki’s strength, Xia Xi unleashed a massive slash that carved a trench through the forest.
• Xia Xi reassured Kiseki that the Demon Slayer Corps would help the family relocate and arrange schooling for Yuichiro and Muichiro.
• The Corps moved the Tokitos to Bunkyo Ward, provided Kiseki with a dojo, and enrolled the children at the same school as Tanjiro and Nezuko.
• After more than a month, Tamayo isolated the compound protein in Tanjuro’s blood and combined it with other ingredients to create an injectable drug for testing on laboratory mice.

Xia Xi and Tamayo tested their first-generation New Demon Slayer Mark vaccine on a laboratory mouse, using Tanjuro’s blood to create a safer mark that consumed energy instead of burning through its host’s lifespan. After seeing the mouse survive, Tanjuro realized the drug could give powerful swordsmen a path to greater strength, though its effects varied.

• Tamayo explained to Tanjuro that the experimental vaccine aimed to prevent marked hosts from dying of organ failure by changing how the mark used energy.
• Yushiro prepared the golden Sun Wheel drug and the blue Moon Shadow drug, and Tamayo injected the golden dose into a marked mouse.
• As the mouse convulsed and its mark faded, Xia Xi urged Tamayo to inject Moon Shadow before the creature could die; the mouse then stabilized.
• Xia Xi explained that the mouse’s early blue dose limited its physical boost, while other mark colors could produce much greater enhancements.
• Xia Xi calculated that a powerful mark could raise Tanjuro’s strength dramatically and saw potential for safer marks to help the Demon Slayer Corps’ strongest fighters.

Xia Xi and Tamayo’s experiments produced a new kind of mark in several white mice, and the group named them War Marks as they planned further trials. Xia Xi then tried to recruit Butterfly Mansion physicians to help Tamayo, but Shinobu’s suspicions and Kanae’s protective resolve gave way to questions about Xia Xi’s recent “training.”

• Tamayo and Xia Xi observed that some mice developed dark yellow or dark gold marks without dying, while unsuccessful subjects suffered only temporary weakness.
• Xia Xi, Tanjuro, and Tamayo settled on the name War Marks and discussed confirming the mice’s health before moving on to trials with Butterfly Mansion physicians and volunteers.
• Xia Xi asked Tamayo whether she was ready to be introduced to the Demon Slayer Corps, and Tamayo trusted him to prepare the physicians for meeting her.
• At Butterfly Mansion, Shinobu Kocho objected to cooperating with a demon who had eaten people, while Kanae supported meeting Tamayo and promised to kill her if she proved wicked.
• When Xia Xi described Tamayo as a beautiful, fair-skinned woman, Kanae unconsciously dented the table and Shinobu demanded to know where he had been spending his time “training.”

Xia Xi tried to calm the Kocho Sisters’ jealousy over his working relationship with Tamayo, while Ye Ying encouraged them to share him. At the research institute’s first meeting with the Butterfly Mansion’s medical team, Shinobu and Yushiro clashed until Xia Xi persuaded Yushiro to apologize.

• Shinobu warned Xia Xi that Kanae was angry about his close work with Tamayo, and Xia Xi explained that Tamayo’s assistant Yushiro and several Demon Slayer Corps members were also around.
• Ye Ying told Kanae and Shinobu that she would share her favorite things, including Xia Xi, and Kanae praised her kindness.
• Tamayo and Yushiro met Kanae, Shinobu, and four Butterfly Mansion physicians for the research institute’s first meeting with the medical department.
• Yushiro insulted the women, and Shinobu snapped back by mocking his chances of winning Tamayo’s affection.
• Xia Xi warned Yushiro that Shinobu could beat him and that driving the physicians away might lead the Corps to send male doctors instead, so Yushiro reluctantly apologized to Shinobu.

Tamayo presented her research to the Butterfly Mansion physicians and began sharing the Research Institute’s work with them. As Shinobu and Kanae grew closer to Tamayo, Shinobu’s suspicion eased and Kanae found a kindred spirit in her.

• Tamayo presented her research on the Demon King’s origins and the War Mark drug, impressing the Butterfly Mansion members.
• Tamayo encouraged Kanae about conveying her feelings, then advised Xia Xi not to overlook the people around him; Xia Xi misunderstood and thought she meant Giyu or Kyojuro.
• The Medical Department took over much of the Humanization Improvement and War Mark drug work, freeing Tamayo to focus on her Demon King-Specific Poison.
• Shinobu and Yushiro frequently argued while working together, but Shinobu came to respect Tamayo after hearing her accept punishment for her past and seeing her work herself to exhaustion.
• Shinobu gradually stopped carrying her Nichirin Blade in the Research Institute, while Kanae and Tamayo bonded over medicine, flowers, and the possibility of humans and demons coexisting.

Tamayo and Kanae discussed their research and the growing strength of the Demon Slayer Corps while taking a break at the institute. Tamayo concluded that Xia Xi’s arrival had driven the Corps’ unprecedented progress and that Mr. Kurumaji was nearing Yoriichi Tsugikuni’s level.

• Tamayo rested in the courtyard with Kanae and described her progress tracing Muzan Kibutsuji’s blood and developing a drug to counter his abilities.
• Kanae told Tamayo that most mice developed weaker martial marks, while crimson-gold marks remained rare, and they discussed ways to increase the chance of producing stronger marks.
• Tamayo compared the current Demon Slayer Corps with the Sengoku generation and praised its numbers, strength, medical care, and logistics.
• Kanae pointed out that the Corps’ advances had come after Xia Xi arrived, and Tamayo agreed that Mr. Kurumaji had helped make their collaboration possible.
• Tamayo reflected that Mr. Kurumaji was already close to catching up with Yoriichi Tsugikuni.

Tamayo reassured Kanae that Xia Xi was different from Yoriichi because he grew stronger with the help of others. Weeks later, the Martial Mark Drug was approved for human trials, and Kanae volunteered to be the first test subject despite Shinobu's fears.

• Kanae asked Tamayo whether Xia Xi resembled Yoriichi, and Tamayo said Xia Xi had grown gradually through his own efforts and the support of others.
• Tamayo told Kanae that Xia Xi would not face Muzan alone, easing Kanae's worries that he might die.
• Several weeks later, Tamayo announced that the Martial Mark Drug had passed its laboratory observation period and was ready for small-scale human trials.
• Shinobu reported that volunteers had been recruited, but Kanae stepped forward to test the drug before the other Corps members arrived.
• Kanae reassured Shinobu that the Hashira should bear risks rather than leave them to others, and Shinobu prepared emergency supplies.
• Tamayo injected Kanae with the drug called Sunlight while Yushiro recorded the data.

Kanae endured the painful awakening of her War Mark and discovered that it greatly increased her strength while consuming energy. She also found she could activate and deactivate the mark at will, leaving Tamayo astonished by the breakthrough.

• Kanae endured the War Mark drug’s escalating pain as Shinobu Kocho held her hand and refused to give her the slow-release agent.
• After twenty-one minutes, reddish-gold markings appeared on Kanae’s face, and the doctors confirmed that her temperature and heartbeat were stabilizing.
• Tamayo administered the final Moon Shadow dose, and Kanae tested her enhanced strength before turning to the high-calorie food prepared for her.
• Kanae discovered she could make the War Mark fade by closing her eyes and concentrating.
• At Tamayo’s request, Kanae activated the War Mark again, surprising the others because the laboratory mice had been unable to switch theirs off.

After using the War Mark serum, Kanae demonstrated her greatly enhanced speed and mastered the Bright Red Nichirin Blade. Xia Xi judged that she could now contend with an Upper Rank, while Kanae hoped to fight beside him; Tanjuro arrived for another blood draw as the serum experiments continued.

• Kanae used Flower Breathing to show Shinobu Kocho how much the War Mark had increased her speed.
• Kanae activated the Grip of Ten Thousand Jun and turned her Nichirin Blade bright red, impressing Shinobu.
• Xia Xi returned to find Kanae's Energy Level had risen to 568 and examined her after noticing her War Mark.
• Kanae used Total Concentration, and Xia Xi assessed her strength as roughly equal to Upper Four and sufficient to hold off Akaza for a while.
• Kanae told Xia Xi she could help him now, and he promised to look forward to fighting beside her.
• Tanjuro arrived for his routine blood draw, and Xia Xi realized the serum experiments required far more blood from a human than from lab mice.

Xia Xi convinced Tanjuro to receive a scarce dose of the Martial Mark Drug, which transformed into an unprecedented bright-gold War Mark. The chapter ended with Tanjuro’s Body attribute soaring into the Strong Hashira stage.

• Xia Xi arranged for Tamayo to draw more of Tanjuro’s blood for the Martial Mark Drug’s human-use trials, and Tanjuro agreed after hearing that he and his children would receive priority doses.
• Xia Xi offered Tanjuro a dose reserved for the Nine Hashira, and Tanjuro accepted after Xia Xi said the Corps could replace it soon.
• Tamayo injected Tanjuro with the Martial Mark Drug, but he initially felt only warmth despite his temperature rising to nearly 39 degrees.
• A dark-gold War Mark appeared on Tanjuro’s forehead, shifted to red-gold, and then settled into pure bright gold.
• Xia Xi saw Tanjuro’s Energy Level rise from 384 to 615 as his Body attribute climbed from 109 to 341.

Tanjuro awakened an exceptionally powerful Heavenly War Mark, and Tamayo’s research explained his unusual compatibility with the drug. After returning home to his family in Tokyo, he heard Kie’s plan for a special outing together to celebrate their upcoming wedding anniversary.

• Tanjuro tested his new strength with Xia Xi, who judged that his full combination of abilities could contend with at least two Akaza-level opponents.
• Tamayo concluded that Tanjuro’s Kamado heritage and unusual biology gave him perfect compatibility with the War Mark drug.
• Xia Xi named the War Mark grades Heavenly, Earth, and Mysterious, while dismissing the weakest marks as failed products.
• Tanjuro returned to Tokyo, reunited with his children and Kie, and shared pastries with the family before dinner.
• Kie asked Tanjuro to visit Asakusa with her in a few days to shop for the children’s yukata and attend Hizakura Tayū’s rare performance as an anniversary surprise.

As the Hashira received Tamayo’s Martial Mark Drug, Shinjuro learned the truth about Yoriichi Tsugikuni and resolved to correct his family’s history. Gyomei then awakened a brilliant golden War Mark, surprising Tamayo and Xia Xi and leaving them to reconsider what made such a mark possible.

• Tamayo treated the Hashira in order of strength, while Gyomei voluntarily let others receive their injections first.
• Tamayo told Shinjuro how Yoriichi’s family was killed, Muzan escaped him, and the Corps expelled him after his brother’s betrayal; Shinjuro decided to revise the Book of Successive Flame Hashira.
• Tengen Uzui received his injection, admired his awakened War Mark, and invited Tamayo and Xia Xi out for a drink before Yushiro chased him away with a broom.
• Gyomei arrived at the institute and reassured Tamayo and Yushiro with his kindness despite his imposing size.
• Gyomei awakened a brilliant golden War Mark, and the force released afterward cracked glassware and windows, astonishing Tamayo and Xia Xi.

Xia Xi reflected on Gyomei Himejima’s immense strength after the Great Monk awakened a golden War Mark, while the Demon Slayer Corps continued growing stronger. As Kanae Kocho’s coming-of-age celebration approached, Xia Xi prepared a special Nichirin Blade for her.

• Xia Xi judged that Gyomei Himejima, empowered by his golden War Mark, had become strong enough to rival Xia Xi’s former strength against Kokushibo.
• Gyomei urged Xia Xi to prioritize his own survival, then privately resolved to protect him even at the cost of his life.
• Xia Xi’s Farm System accumulated Achievement Points as the Hashira and other swordsmen grew stronger, and Kiseki Tokito’s Moon Breathing progress brought him close to Hashira-level strength.
• Shinobu Kocho, Tamayo, and the other Hashira prepared gifts and arrangements for Kanae Kocho’s coming-of-age celebration.
• Xia Xi traveled to Yokohama and forged a high-quality Nichirin Blade for Kanae before the day preceding her celebration arrived.