Chapter Summaries

Xia Xi balanced forging practice with mining and developed a medicinal bath that boosted his Body before its effects began to diminish. After reaching Forging LV.3, his technique improved so dramatically overnight that Tiezhen said it nearly matched his own.

• Xia Xi used hot spring water and his Medicine and Pharmaceutical Crafting skills to develop a medicinal bath that raised his Body by 2 points, though repeated use weakened its effect.
• Xia Xi spent nights searching abandoned and idle mines to raise his Mining skill, puzzling the Swordsmith Village residents with his late-night ore collecting.
• Tiezhen had Xia Xi practice the fundamentals of forging by making a hoe from Crimson Red Iron Sand and taught him practical techniques.
• Xia Xi entered a forging Flow State during practice, and his Forging skill reached LV.3 by the end of the week.
• The day after his breakthrough, Xia Xi forged with exceptional precision, prompting Tiezhen to marvel that his technique nearly matched his own.

Xia Xi treated Tetsujin’s appendicitis and learned about his family’s Mechanism Technique. The chapter ended with Hotaru Haganezuka charging at Xia Xi and bouncing off as if he had hit an iron wall.

• Xia Xi met the ailing Tetsujin and diagnosed him with appendicitis.
• Xia Xi performed an appendectomy, brought Tetsujin home, and gave him recovery instructions.
• Xia Xi asked Tetsujin to show him his family’s Mechanism Technique, and Tetsujin explained that his family had lost most of its craft.
• Hotaru Haganezuka burst into the house, mistook Xia Xi for an attacker, and charged at him.
• Xia Xi’s unseen defense sent Hotaru Haganezuka bouncing back, and Xia Xi turned to ask what Tetsujin had been saying.

Haganezuka rushed to Tetsujin’s home after hearing that Xia Xi had cut him open, but learned that Xia Xi had treated his illness. After witnessing Xia Xi’s forging skill, Haganezuka became his eager apprentice, giving Xia Xi another source of swordsmithing experience.

• Haganezuka burst into Tetsujin’s room and accused Xia Xi of stabbing him, but Tetsujin explained that Xia Xi had treated his illness.
• Haganezuka apologized for his mistake, then challenged Xia Xi to prove his swordsmithing skill.
• Xia Xi agreed to forge while Haganezuka shared his experience, and Haganezuka watched in awe as Xia Xi demonstrated his technique.
• Haganezuka eagerly begged Xia Xi to teach him, accepting Xia Xi’s teasing demands before joining him as an apprentice.
• From the following day, Haganezuka helped Xia Xi in the village chief’s forge and learned from him, while Xia Xi gained more swordsmithing experience.

After forging a pure-white Nichirin Blade and explaining his unusual methods to Haganezuka, Xia Xi continued practicing in the Swordsmith Village. A change in his Breathing Style and grip sparked a crimson-hot hammer blow, unlocking the Grip of Ten Thousand Jun skill.

• Xia Xi forged a sturdy Nichirin Blade that turned pure white in his hands, surprising Haganezuka.
• Haganezuka examined the blade and asked about Xia Xi’s unusual alloying and hot-oil quenching methods, which Xia Xi passed off as a secret formula.
• Over the following days, Xia Xi practiced forging while his [Forging] progress steadily increased.
• On the fifth night, Xia Xi switched from Stone Breathing to Dawn Breathing while hammering a low-quality iron ingot, and his changing rhythm and grip caused the ingot to split and fuse back together.
• Xia Xi’s hammer turned blazing crimson as he struck, and the system unlocked the Grip of Ten Thousand Jun skill.

Xia Xi discovered that Grip of Ten Thousand Jun could turn Crimson Red Iron Sand weapons into Bright Red Nichirin Blades, letting him unleash heat-based ranged attacks and strikes that passed through obstacles. After accidentally destroying two ornamental trees, he considered the technique’s potential against Upper Rank demons and planned to teach it to Gyomei Himejima.

• Xia Xi tested Bright Red Nichirin Blade mode on his forging hammer, Severing Wind, and Nichirin Blade blanks, finding that weapons containing Crimson Red Iron Sand could glow red-hot.
• Xia Xi used the heated Fist Armor to fire scorching blasts that damaged and eventually toppled a tree, then developed Ten Kings Spear: Red Flash to strike through another tree and a wall.
• Haganezuka found Xia Xi amid the destruction, and Xia Xi learned that Village Chief Tiezhen and Mr. Hotaru would return the next day.
• Village Chief Tiezhen returned to find the damaged backyard wall rebuilt and both ornamental trees replaced with jujube trees.
• Xia Xi studied his new skill and concluded that Bright Red Nichirin Blade could suppress demon regeneration and might help Hashira fight Upper Rank demons.
• Xia Xi decided to test whether he could teach the technique to Gyomei Himejima, whose Physique was the highest among the nine Hashira.

Xia Xi unlocked Mining and used the skill to discover Scarlet Crimson Iron Sand beneath an abandoned mine near the Swordsmith Village. He led the smiths in excavating it and proved the deposit was real, leaving them eager to honor him for his discovery.

• Xia Xi unlocked Mining and surveyed nearby ore deposits, finding substantial reserves of Scarlet Crimson Iron Sand beneath a depleted copper mine.
• Xia Xi brought Ginzo, Haganezuka, and other swordsmiths to the mine and directed them to dig an inclined shaft.
• Xia Xi used his strength, Mining skill, and Bright Red Blade tools to excavate far faster than the rest of the crew could work.
• The miners uncovered dark red iron ore before sunset, confirming Xia Xi's discovery.
• A young blacksmith bowed to Xia Xi and called him a god of forging and mining.

After helping Swordsmith Village secure a new ore vein, Xia Xi decided to seek higher-quality ore for his own weapon and rested in the village hot spring. There, he found Shinjuro Rengoku in a profound slump, and Shinjuro called sword forging a futile effort.

• The new Crimson Red Iron Sand vein eased the Demon Slayer Corps' blade shortage, and Kagaya Ubuyashiki sent Xia Xi praise.
• Xia Xi told Tiezhen he wanted higher-quality ore for his weapon, but learned that attempts to create artificial Crimson Red Iron Sand had failed.
• After exhausting himself with mining and training, Xia Xi went to relax in Swordsmith Village's hot spring.
• Shinjuro Rengoku and Ruka Rengoku joined Xia Xi; Ruka explained that Shinjuro had come to improve his mood while she recuperated.
• When Ruka mentioned Xia Xi's forging lessons, Shinjuro said forging swords was wasted effort and described it as a mortal's futile struggle.

Shinjuro told Xia Xi that reading the Rengoku family chronicle had left him despairing over how far later Hashira fell short of Yoriichi Tsugikuni and Sun Breathing. Xia Xi challenged his view that the other Breathing Styles were worthless, and Shinjuro corrected him when he called Flame Breathing Fire Breathing.

• Lady Ruka explained that Shinjuro had been training desperately because he wanted to stand beside the younger Demon Slayers and protect them.
• Ruka described the Book of Successive Flame Hashira, a family chronicle that recorded Yoriichi Tsugikuni as the source of Breathing Styles and the first Flame Hashira's transformation into a Demon Slayer.
• Shinjuro asked Xia Xi about Sun Breathing, and Xia Xi revealed that he also knew of Moon Breathing, surprising Shinjuro.
• Shinjuro explained that Sun Breathing was the original style and that later Breathing Styles were simplified imitations, while Yoriichi had mastered techniques that others spent their lives pursuing.
• Shinjuro lamented that even Yoriichi had failed to destroy Muzan and the demon accompanying him, leaving him doubtful about the purpose of later Hashira's efforts.
• Xia Xi asked whether Sun Breathing or Fire Breathing had killed more demons, and Shinjuro corrected him: it was Flame Breathing.

Xia Xi challenged Shinjuro’s despair over Yoriichi Tsugikuni, reminding him that the Rengoku family’s purpose was to protect people and that his ancestors had continued their duties despite reading about the legendary swordsman. Shinjuro regained some resolve and asked Xia Xi to speak with him again the next day, while Xia Xi wondered about Yoriichi’s strength and his failure to defeat Muzan Kibutsuji.

• Xia Xi argued that the many demons killed by generations of Flame Breathing swordsmen and other Demon Slayer Corps members mattered more to humanity than one legendary swordsman’s achievements.
• Ruka reminded Shinjuro that the Rengoku family fought to protect people, and Xia Xi pressed him to consider how many lives killing ordinary demons could save.
• Xia Xi pointed out that Shinjuro’s father and grandfather had continued training and killing demons after reading the Flame Hashira book, then urged Shinjuro not to disgrace his ancestors by giving up.
• Shinjuro’s spirits lifted, and he thanked Xia Xi for helping him and his family; Xia Xi replied with embarrassment at Shinjuro’s heartfelt words.
• Xia Xi wondered about Yoriichi Tsugikuni’s abilities and why he had failed to defeat Muzan Kibutsuji.
• After leaving the hot spring, Shinjuro invited Xia Xi to talk with him the next day about Breathing Styles and other matters.

Xia Xi learned from Shinjuro Rengoku that Michikatsu Tsugikuni had become a demon and likely held the rank of Upper Rank One, while Yoriichi had spared him. Xia Xi then demonstrated a new sword technique that turned Shinjuro’s Nichirin Blade scarlet.

• Shinjuro Rengoku visited Xia Xi at Village Chief Tiezhen's workshop to discuss Sengoku-era records.
• Shinjuro told Xia Xi that Michikatsu Tsugikuni had killed an Ubuyashiki Oyakata and become a demon, and they reasoned he was likely Upper Rank One.
• Shinjuro explained that Yoriichi had encountered Michikatsu in his later years but deliberately held back and failed to kill him.
• Xia Xi asked to demonstrate a new weapon technique, and Shinjuro lent him his Nichirin Blade.
• Xia Xi used the technique to turn the blade a brilliant scarlet, leaving Shinjuro astonished.

Shinjuro Rengoku learned that Xia Xi’s Bright Red Nichirin Blade technique could be taught and asked him for instruction. He stayed in the Swordsmith Village to train, where Xia Xi’s brutal sparring left him badly bruised.

• Shinjuro recognized the danger of Xia Xi’s bright red blade and wondered whether Xia Xi was related to Yoriichi or Michikatsu Tsugikuni.
• Xia Xi deactivated the blade’s red state and explained that the technique could be learned, though it required exceptional physical ability.
• Shinjuro asked Xia Xi to teach him, and Xia Xi agreed after Shinjuro called him Master Xia Xi.
• Shinjuro wrote to Kagaya Ubuyashiki for extra leave and began intensive physical training and combat sparring with Xia Xi.
• Xia Xi’s ruthless sparring left Shinjuro bruised on the first day, and Ruka teased him when he returned to their lodging.
• After the second day of training, Shinjuro came back with bruises around both eyes, and Ruka joked that he resembled a rare animal.

Xia Xi trained Shinjuro in swordsmanship and the Bright Red Nichirin Blade, using brutal sparring and potent medicinal baths to build his strength. After seven days, Shinjuro mastered the Bright Red Blade and Xia Xi earned five achievement points.

• Xia Xi trained Shinjuro and taught him how to activate the Bright Red Nichirin Blade while Ruka watched his repeated defeats with quiet amusement.
• Shinjuro first managed to make his Nichirin Blade flicker red, so Xia Xi gave him a powerful medicinal bath to improve his physical attributes.
• The bath made Shinjuro furious and unusually powerful, and he fought Xia Xi in a battle that left the nearby mountain forest devastated.
• Xia Xi continued Shinjuro's medicinal-bath training, while Ruka stopped attending and nearby households moved away because of the noise.
• On the seventh day, Shinjuro made his Nichirin Sword glow steadily red, mastered the Bright Red Blade, and earned Xia Xi five achievement points.

Shinjuro mastered the Bright Red Nichirin Blade technique and came to believe Xia Xi would lead the Demon Slayer Corps to victory, while Shinjuro's exhaustion left him unable to fulfill Ruka's request that night. A few days later, Xia Xi hosted a sukiyaki party, where the recovering Tetsushin arrived and was pulled inside by Haganezuka.

• Shinjuro mastered the Bright Red Nichirin Blade technique and praised Xia Xi's talent and strength.
• Shinjuro bowed to Xia Xi and vowed to support him until he was ready to lead everyone to victory.
• That night, Shinjuro told Ruka he would show her his new technique the next day, then declined to continue their intimacy because he was exhausted.
• A few days later, Xia Xi hosted a sukiyaki party for the Swordsmith Village residents, and Haganezuka preferred eating mitarashi dango.
• Tetsushin arrived to thank Xia Xi with gifts, but Haganezuka pulled him into the party and handed him a skewer of rice dango.

After recovering from his injuries, Tetsujin showed Xia Xi his mechanical toys and his family’s ancient Combat Puppet. Xia Xi recognized the puppet as Yoriichi Type Zero, though he blurted out the mistaken name “Red Di Tian.”

• Tetsujin visited Xia Xi to thank him for treating his injuries and gave him rare ores and a mechanical bird.
• Xia Xi visited Tetsujin’s home, examined his mechanical creations, and discovered that his Carpenter skill revealed information about them.
• Tetsujin explained that his family’s mechanical craft had been passed down through generations and showed Xia Xi an old Combat Puppet kept in a coffin-like box.
• Tetsujin opened the box, revealing a six-armed puppet holding Nichirin swords, and Xia Xi identified it as Yoriichi Type Zero before mistakenly calling it “Red Di Tian.”

Xia Xi examined and sparred with Tetsujin’s family heirloom, Yoriichi Type Zero, after promising Kotetsu he would not break it. He easily dodged the puppet’s relentless attacks, leaving Tetsujin and Kotetsu astonished by his skill.

• Xia Xi inspected Yoriichi Type Zero and asked Tetsujin whether the combat puppet could use a Breathing Style.
• Tetsujin explained the puppet’s abilities and hesitated to activate it because he feared it might be damaged.
• Kotetsu objected to Xia Xi touching the heirloom, but Xia Xi promised not to break it and swore he could repair it if necessary.
• Tetsujin wound up Yoriichi Type Zero, which locked onto Xia Xi and attacked with rapid combinations from its six swords.
• Xia Xi calmly evaded the puppet’s attacks without striking back, while Tetsujin and Kotetsu watched in amazement.

Xia Xi fought Yoriichi Type Zero, identified its strengths and predictable attack patterns, then disabled it without meaning to damage it. The puppet stopped moving, but one of its old arms fell off, leaving Xia Xi startled.

• Xia Xi observed that Yoriichi Type Zero used its six arms and fixed sequences to compensate for its limited strength.
• Xia Xi recognized repeated patterns in the puppet’s 108 recorded moves and easily blocked its attacks with one hand.
• Xia Xi judged the puppet valuable as a training opponent and fighting force despite its flaws.
• Xia Xi disabled all six arms by manipulating their joints, then switched off the puppet.
• Kotetsu pointed out that one of the puppet’s arms had fallen off, and Xia Xi exclaimed in shock.

After accidentally breaking Yoriichi Type Zero’s arm, Xia Xi promised Kotetsu he would repair the puppet and persuaded Tetsujin to teach him Mechanism Technique. He built a Mechanism Frog, which stopped after only eight hops despite supposedly running for half an hour.

• Xia Xi accidentally dislodged Yoriichi Type Zero’s arm, and Kotetsu cried over the damaged puppet.
• Tetsujin examined the arm and said the damage was repairable, though the work would take about a day.
• Xia Xi promised Kotetsu he would repair Yoriichi Type Zero and asked Tetsujin to teach him Mechanism Technique.
• Xia Xi helped gather materials and watched Tetsujin begin dismantling the puppet before studying beginner mechanism drawings.
• Tetsujin gave Xia Xi a Mechanism Frog kit, and Xia Xi assembled the toy by following his instructions.
• Xia Xi wound the finished frog, but it hopped only eight times before stopping.

Xia Xi struggled to learn Mechanism Puppet Technique by making mechanical frogs, then mastered the blueprints Tetsujin had and produced increasingly skilled creations. With no plans for Yoriichi Type Zero, Xia Xi proposed replacing its damaged shell and inspecting its mechanism, and Tetsujin agreed.

• Xia Xi borrowed Tetsujin’s tools and spent nights making mechanical frogs until the system recognized his work as Mechanism Puppet Technique.
• Xia Xi unlocked a crafting minigame, made a Mechanism Butterfly, and celebrated its creation before burning his pile of wooden frogs.
• Xia Xi practiced the blueprints for mechanical toys and eventually impressed Tetsujin with an ordinary-quality Mechanism Bird.
• Xia Xi reached Mechanism Puppet Technique Lv. 1 and proposed making a replacement shell for Yoriichi Type Zero while inspecting its inner mechanism.
• Tetsujin agreed to Xia Xi’s plan and thanked him for taking on the work.

Xia Xi reverse-engineered Yoriichi Type Zero by refurbishing the puppet until the System unlocked its blueprint. Just as Shinjuro Rengoku arrived and mistook the restored puppet for Yoriichi Tsugikuni, Xia Xi hurried to stop him from attacking.

• Xia Xi examined Yoriichi Type Zero while helping Tetsujin replace its shell, and the System began analyzing the puppet's blueprint.
• Xia Xi supplied new parts over several days, and he and Tetsujin replaced worn components, including the rusty Nichirin Blade in the puppet's spine.
• Xia Xi completed the refurbishment, unlocked the Yoriichi Type Zero blueprint, and gave the puppet a replica of Yoriichi Tsugikuni's outfit.
• Kotetsu cried with happiness at Type Zero's restored appearance, and Xia Xi noticed its Energy Level had risen from 357 to 371.
• Shinjuro Rengoku saw the puppet and mistook it for Yoriichi Tsugikuni, then nearly drew his Bright Red Blade before Xia Xi stopped him.

Xia Xi stopped Shinjuro from fighting Yoriichi Type Zero and promised to make him a Combat Puppet. After Shinjuro left, Xia Xi began building one himself, and the chapter ended with the first stage of production complete.

• Shinjuro mistook Yoriichi Type Zero for a demonized Yoriichi Tsugikuni and drew his Nichirin Blade, but Xia Xi explained that it was a mechanical puppet.
• Shinjuro asked to fight the puppet, but Xia Xi and Tetsujin persuaded him to stop, and Xia Xi promised to make him a Combat Puppet someday.
• Shinjuro gave Xia Xi a flame-patterned Morale-Boosting Headband from Kyojuro and reminded him to return to his duties at the Sendai Dojo.
• After Shinjuro left, Xia Xi used the newly unlocked Yoriichi Type Zero blueprints and Tetsujin's tools to begin building a Combat Puppet.
• Xia Xi finished the first production stage by forging a rough steel skeleton and pretreating wood, while the panel showed production at 1/21.