Chapter Summaries

Su Chen saved Kagaya Ubuyashiki by using fighting spirit to awaken his Demon Slayer Mark, breaking the Ubuyashiki Clan’s curse and discovering that his own fighting spirit had grown stronger. He left wondering how to protect Shinobu Kocho and other marked Demon Slayers from shortened lifespans without risking their lives through Cellular Restructuring.

• Kagaya Ubuyashiki stood up and saw that he had awakened a Demon Slayer Mark, then knelt to thank Su Chen for saving him.
• Kagaya Ubuyashiki and Lady Amane promised to remember Su Chen’s kindness and offer him help, but Su Chen fled from their repeated gratitude.
• Su Chen realized that saving Kagaya Ubuyashiki had prevented turmoil in the Demon Slayer Corps and confirmed that fighting spirit could help someone awaken a Demon Slayer Mark.
• Su Chen discovered that his fighting spirit had recovered and broken through, but he worried that Demon Slayer Marks would shorten the lives of Shinobu Kocho and the other Hashira.
• Su Chen considered using fighting spirit to awaken Shinobu Kocho’s mark and perform Cellular Restructuring, but remembered that one attempt had nearly overwhelmed Kagaya Ubuyashiki.

Su Chen visited the unconscious Muichiro Tokito at the Butterfly Mansion, where Shinobu Kocho told him about her assignment to work with Tamayo and her hatred of demons. After learning his Hashira training would come last, Su Chen asked Shinobu to show him where Zenitsu was staying.

• Su Chen returned to the Butterfly Mansion and learned from Shinobu Kocho that Muichiro Tokito remained unconscious despite having his external injuries treated.
• Shinobu Kocho told Su Chen that Oyakata-sama had ordered her to work with Tamayo, and she insisted she would still hate demons even if one had not eaten anyone.
• Su Chen asked Shinobu what she would do if someone close to her became a demon, and Shinobu said she would protect them but would kill them if they betrayed the humans.
• Shinobu told Su Chen that his Hashira training would be scheduled last, and Su Chen said he had thought of what his training should be.
• Su Chen asked Shinobu where Zenitsu was staying, and she led him toward the inpatient ward, pointing out the blond boy.

Su Chen visited the sleeping Zenitsu at the Butterfly Mansion, where volunteers’ admiration briefly disrupted their conversation. He told Zenitsu that Kaigaku had become a demon and asked what their shared master would do.

• Shinobu Kocho showed Su Chen the injured Zenitsu and explained that he had not woken since his mission.
• Su Chen sent Shinobu Kocho to her experiments and approached Zenitsu, who woke suddenly and feared him.
• A volunteer tried to make Zenitsu answer Su Chen’s questions, but Su Chen sent him away after realizing the volunteers were his fans.
• Su Chen told Zenitsu that Kaigaku had become a demon and asked what their master would do about his former senior.

Su Chen rushed Zenitsu back to Jigoro Kuwajima’s mountain, then revealed he had delayed the news of Kaigaku becoming a demon to keep Jigoro from committing seppuku. Zenitsu agreed to take Su Chen to his grandfather so Su Chen could learn the other Thunder Breathing forms, and they found Jigoro dozing outside his home.

• Su Chen warned Zenitsu that Jigoro might commit seppuku because Kaigaku had become a demon, prompting Zenitsu to hurry home with him.
• Su Chen brought Zenitsu to his mountain in half a day, then explained that he had blacklisted Jigoro from the news so he would not hear about Kaigaku yet.
• Zenitsu realized Su Chen had manipulated him into returning quickly and that delaying the news might have saved Jigoro’s life.
• Su Chen admitted he wanted to learn Thunder Breathing from Jigoro, and Zenitsu agreed to take him up the mountain.
• Zenitsu and Su Chen reached the wooden house and saw Jigoro sitting outside, asleep in a chair.

Su Chen and Zenitsu visited Jigoro Kuwajima, where Zenitsu’s tearful reunion turned into a scolding before Jigoro recognized Su Chen as the Dragon Hashira. When Zenitsu tried to grab Su Chen’s tea, Jigoro unleashed a powerful electrical attack, and Su Chen activated his Time Domain to study it.

• Zenitsu rushed to Jigoro Kuwajima as he napped, knocked him over, and cried that he had feared Jigoro had died by seppuku.
• Jigoro woke, scolded Zenitsu for his remark, and then noticed Su Chen standing behind him.
• Jigoro sensed Su Chen’s tightly controlled Fighting Spirit and asked whether he was a Hashira.
• Su Chen introduced himself as the Dragon Hashira, and Jigoro warmly invited him inside and brewed him tea.
• Zenitsu tried to seize Su Chen’s tea, so Jigoro attacked him with electricity.
• Su Chen activated his Time Domain and focused on Jigoro’s movements to observe how he controlled the electric ions.

Su Chen visited Jigoro Kuwajima with Zenitsu and told him about the Swordsmith Village attack and Kaigaku’s betrayal. Jigoro learned that Kaigaku had become a demon and helped expose the village, and he was left grieving over his former disciple.

• Jigoro Kuwajima defeated Zenitsu, then sat with Su Chen and discussed the Demon Slayer Corps and the Swordsmith Village incident.
• Su Chen told Jigoro that the Swordsmith Village had been exposed and that Tokito remained unconscious after Kokushibo’s attack.
• Jigoro welcomed Zenitsu home and tried to comfort him, but Zenitsu struggled to explain what had happened to Kaigaku.
• Su Chen revealed that Kaigaku had become a demon, and Jigoro tried to kill himself with his hand after Zenitsu took away his Nichirin Blade.
• Su Chen stopped Jigoro and confirmed that Kaigaku had likely exposed the Swordsmith Village’s location, leaving Jigoro devastated.

Su Chen stopped Jigoro Kuwajima from committing seppuku over Kaigaku becoming a demon and challenged him to take responsibility by dealing with his wayward disciple himself. Jigoro decided to go down the mountain to confront Kaigaku, but Su Chen cautioned that there was no need to rush.

• Jigoro Kuwajima asked Su Chen to take Zenitsu as his Tsuguko, but Su Chen refused for now and knocked Zenitsu unconscious so they could talk privately.
• Jigoro took Zenitsu's sword and tried to commit seppuku, but Su Chen stopped him and argued that Jigoro should deal with Kaigaku himself.
• Su Chen accused Jigoro of trying to leave Kaigaku's punishment to him, and Jigoro reconsidered his plan to die before acting.
• Jigoro woke Zenitsu and announced that he would go down the mountain to deal with Kaigaku, while Zenitsu refused to hand over his sword.
• Su Chen told Jigoro that going down the mountain immediately would be too hasty.

Zenitsu promised that Su Chen would learn Thunder Breathing, so Jigoro Kuwajima agreed to demonstrate the style’s forms. After Su Chen watched Jigoro perform the First and Second Forms, Jigoro began preparing to show the Third.

• Zenitsu told Jigoro that he had promised to teach Su Chen Thunder Breathing, and Jigoro protested before agreeing to guide Su Chen.
• Su Chen explained that he knew the First Form but wanted to learn the remaining techniques from Jigoro, the only person who knew the complete style.
• Jigoro demonstrated Thunderclap and Flash, moving so quickly that Su Chen’s Time Domain briefly lost track of him.
• Su Chen analyzed the First Form and recalled how Zenitsu had developed variations such as Sixfold Strike, Eightfold Strike, and Godspeed.
• Jigoro performed the Second Form, Rice Spirit, with five rapid slashes, then began gathering power for the Third Form.

Jigoro Kuwajima demonstrated Thunder Breathing for Su Chen, who instantly learned and improved the Third Form by creating Chidori Stream. Jigoro then performed the remaining forms, while Su Chen recalled Zenitsu’s unique Seventh Form.

• Jigoro Kuwajima began demonstrating Thunder Breathing’s Third Form despite Zenitsu’s worries, and Su Chen quickly developed Chidori Stream from it.
• Jigoro Kuwajima was stunned by Su Chen’s new technique, then faltered when excitement disrupted his breathing; Su Chen healed his age-related ailments with Demon Hand Massage.
• Jigoro Kuwajima prepared to demonstrate the Third Form again, but Su Chen said he had already learned it and asked to see the next form.
• Jigoro Kuwajima angrily demonstrated Thunder Breathing’s Fourth, Fifth, and Sixth Forms while Zenitsu mocked the Fourth Form’s slowness.
• Su Chen recalled Zenitsu’s Seventh Form, Fire Thunder God, and Zenitsu praised Jigoro Kuwajima for demonstrating every form.

Su Chen and Zenitsu persuaded Jigoro Kuwajima not to risk his life searching for Kaigaku, and Su Chen pushed Zenitsu to prepare to face his senior fellow disciple himself. The next morning, Su Chen arrived at the Butterfly Mansion alone.

• Zenitsu tried to fool Jigoro Kuwajima during their sparring, but Jigoro caught on and kept beating him until Su Chen interrupted them.
• Su Chen reflected on his Breathing Styles and his goal of learning every fundamental style to create a stronger one.
• Zenitsu admitted he had been pretending during the sparring and explained that he wanted Jigoro to stay alive; Su Chen and Zenitsu persuaded Jigoro to remain behind.
• On their way back, Su Chen told Zenitsu that he would have to face Kaigaku if they found him, and Zenitsu reluctantly vowed to finish his senior fellow disciple.
• After traveling together all day, Su Chen and Zenitsu parted at the foot of the Demon Slayer Corps' mountain; the following dawn, Su Chen reached the Butterfly Mansion alone.

Su Chen overheard Corps members gossiping about Genya Shinazugawa eating a demon, then asked Shinobu Kocho whether working with demons troubled her. Shinobu said she could accept it for everyone’s sake, and Su Chen left the Butterfly Mansion troubled by his own demon nature and his inability to protect her.

• Two Corps members told Su Chen that Genya Shinazugawa had been seen eating a demon and taking on a monstrous appearance.
• Su Chen met Shinobu Kocho at the Butterfly Mansion and realized she had encountered Chachamaru.
• Su Chen asked Shinobu whether working with demons was difficult for her, and she said it was acceptable if done for everyone’s sake.
• Su Chen reflected that he was a demon himself and feared another tragedy like Kanae Kocho’s, then left to get some air and think about training.
• Shinobu watched Su Chen leave, puzzled and deep in thought.

Aoi Kanzaki told Shinobu Kocho that the Corps was investigating Su Chen after reports that he had become a demon at the Swordsmith Village. When Su Chen left the Butterfly Mansion and armed people arrived looking for him, Shinobu resolved to find a cure that would turn him back into a human.

• Aoi Kanzaki told Shinobu Kocho that the Corps had investigated Genya Shinazugawa and that witnesses claimed Su Chen had turned into a demon at the Swordsmith Village.
• Aoi recounted the rumors about Su Chen, including that he was a Demon Eater, leaving Shinobu shaken as she struggled to accept that he might be a demon.
• Kiyo, Sumi, and Xiao Caihui reported that Su Chen had left down the mountain and that armed people had arrived asking for him.
• Shinobu suspected Su Chen had left before the visitors could confront him and worried that he might leave the Butterfly Mansion.
• Shinobu declared that she would find a cure for Su Chen and thought of Tamayo as someone who might help.

Su Chen learned Stone Breathing from Gyomei and fused it with the other four basic Breathing Styles in his Memory Palace, creating a style he named Light Breathing. He emerged from his meditation beneath the waterfall as the surrounding snow melted from his rising body heat.

• Shinobu Kocho told Shénqíkù to send the people outside away before heading to her Laboratory.
• Su Chen meditated beneath a waterfall while Gyomei discussed the upcoming training and Su Chen’s reluctance to undergo examinations.
• After learning Stone Breathing from Gyomei, Su Chen entered an epiphany and brought the five basic Breathing Styles together in his Memory Palace.
• Su Chen’s fusion produced a golden Light Dragon that made the Sun Dragon avert its gaze, and he named the new style Light Breathing.
• Su Chen left his Memory Palace and opened his eyes as his rising body heat melted the snow around him.

Su Chen developed Light Breathing while the Demon Slayer Corps prepared its Hashira training and investigated rumors that he was a demon. At the Ubuyashiki Residence, Kagaya Ubuyashiki planned to have Su Chen teach the Corps, and Lady Amane began explaining Kagaya’s apparent recovery to the Stone Hashira.

• Su Chen practiced with his Nichirin Blade, and the Stone Hashira sensed traces of several Breathing Styles in his aura before Su Chen called his style Light Breathing.
• The Corps arranged the Hashira training schedule, leaving Su Chen’s training undecided while he continued studying alone.
• Kagaya Ubuyashiki told Lady Amane and the Stone Hashira that the rumor about Su Chen being a demon might have come from leaked information within the Corps, and said he would investigate.
• Kagaya Ubuyashiki suggested placing Su Chen’s training last and having him lecture the Corps on slaying Upper Ranks.
• The Stone Hashira sensed that Kagaya Ubuyashiki’s vitality had improved, and Lady Amane began explaining the couple’s act to him.

Obanai Iguro visited the Butterfly Mansion under the pretext of getting medicine for Kaburamaru, hoping to learn about Su Chen’s feats and new Breathing Style. He finally encountered Su Chen and asked to see the technique, leaving Kaburamaru’s minor injury untreated.

• Lady Amane told the Stone Hashira that Kagaya Ubuyashiki’s health had improved and that he had awakened a Demon Slayer Mark, and the Stone Hashira promised to investigate the rumors tarnishing Su Chen’s name.
• As the Hashira returned to the Corps’ base, Obanai Iguro went to the Butterfly Mansion, claiming Kaburamaru needed medicine while hoping to ask Su Chen about his new Breathing Style and battles.
• Aoi Kanzaki told Obanai that Su Chen had been training and was rarely at the mansion, and Obanai grew curious about what he was doing.
• Su Chen arrived in the courtyard and said he had been testing a new Breathing Style on the mountain.
• Obanai asked Su Chen to show him the new Breathing Style, then dismissed Kaburamaru’s wound as a minor injury.

Su Chen returned to the Butterfly Mansion and began treating patients, despite the Serpent Hashira urging him to share his combat experience instead. After examining Kaburamaru, Su Chen hinted that Obanai had a condition of his own, leaving Obanai asking what he had discovered.

• Su Chen refused to demonstrate his Breathing Style and went to the treatment room, followed by Aoi Kanzaki and the Serpent Hashira.
• Patients waiting at the Butterfly Mansion speculated that Shinobu Kocho had stopped seeing them because she had been dumped by Su Chen.
• Su Chen took Shinobu Kocho’s place at the consultation desk and began treating the patients.
• The Serpent Hashira told Su Chen to train the Corps instead, but Su Chen insisted that treating patients was also important.
• The Serpent Hashira silenced the complaining patients with his authority, then sat down and presented Kaburamaru for treatment.
• Su Chen said Kaburamaru was not ill and suggested that the Serpent Hashira had a condition, prompting Obanai to ask what he had found.

Obanai Iguro asked Su Chen for advice on winning Mitsuri Kanroji’s heart, choosing that dream over healing his face or Kaburamaru’s injuries. Su Chen learned from Aoi Kanzaki that Shinobu Kocho was developing a demon-to-human reagent because she wanted Su Chen to turn back.

• Su Chen recognized Obanai Iguro’s old chin injury and teased him about being lovesick, prompting Obanai to ask for advice.
• Obanai offered to register his Hashira title under the Butterfly Mansion as payment, then chose advice about his dream over treatment for his face.
• Su Chen told Obanai to confess, and Obanai left wondering whether Mitsuri Kanroji might like him too.
• Aoi Kanzaki asked who Obanai planned to confess to, then assured Su Chen that Shinobu Kocho only cared for him.
• Aoi told Su Chen that Shinobu was working with Tamayo on a reagent to turn demons back into humans because she wanted Su Chen to turn back.

Muichiro Tokito awoke at the Butterfly Mansion, and Su Chen helped loosen the lock on his memories while assuring him they would return gradually. Su Chen stayed at the mansion after Kanao Tsuyuri asked him not to leave, then accepted her suggestion to teach Breathing Styles during Hashira training; the chapter ended with him standing outside the gates and activating the Time Domain.

• Aoi Kanzaki told Su Chen that she and the others trusted him, even if he was a demon, and Kiyo announced that Tokito had awakened.
• Su Chen questioned Muichiro Tokito, used the Time Domain to restore his strength, and explained that Tokito's locked memories would return slowly.
• Kanao Tsuyuri hugged Su Chen and asked if he was leaving because of rumors that he was a demon, and he promised to stay at the Butterfly Mansion.
• Su Chen continued treating patients and guiding Kanao's sword practice, and Kanao suggested that he teach the Hashira trainees suitable Breathing Styles.
• Su Chen agreed to Kanao's suggestion, then left the Butterfly Mansion gates and activated the Time Domain.

Su Chen’s body began evolving under Muzan’s blood, leaving him craving blood and struggling to control his strength. Kanao Tsuyuri stopped him from leaving the Butterfly Mansion, but a sudden surge in his blood made him realize Hashira Training had begun.

• Su Chen examined his rapidly changing body and realized Muzan’s blood was driving a painful evolution that left him craving blood and oxygen.
• Su Chen tried to leave the Butterfly Mansion so no one would see him lose control, but Kanao Tsuyuri embraced him.
• Su Chen pushed Kanao away and warned her to stay back as his strength and hunger threatened to overwhelm him.
• Kanao Tsuyuri cried and begged Su Chen not to leave, and her presence calmed him enough to promise he would stay.
• Su Chen’s blood began boiling again, and he asked Kanao Tsuyuri whether Hashira Training had started; she said it had begun two days earlier.

Su Chen sensed Muzan’s presence at the Demon Slayer Corps’ base and realized Muzan had arrived earlier than expected. Muzan entered Kagaya Ubuyashiki’s residence, where Kagaya and Amane waited to face him.

• Su Chen sensed a powerful demon nearby and concluded that Muzan had come to the Demon Slayer Corps’ base.
• Su Chen noticed Muzan’s presence was approaching the Ubuyashiki residence and wondered whether events had been brought forward.
• Kagaya Ubuyashiki and Lady Amane reaffirmed their resolve as they waited for Muzan.
• Muzan passed through the mist and entered Kagaya Ubuyashiki’s residence.
• Kagaya Ubuyashiki faced Muzan and named him as the demon their family had hunted for a thousand years.