Chapter Summaries

After transmigrating to Mount Natagumo, Su Chen used his heaven-defying comprehension to gain several abilities and awaken a demon slayer mark. Shinobu Kocho rescued him from a demon and took him toward the Butterfly Mansion after he agreed to join the Demon Slayer Corps, but he fainted from mental exhaustion.

• Su Chen realized he had transmigrated to Mount Natagumo and received heaven-defying comprehension.
• When a demon attacked, Su Chen comprehended Crooked-Mouth Smile, the High-Frequency Heartbeat Technique, and Heat Breathing, then dodged its lunge.
• Shinobu Kocho killed the demon with Insect Breathing and noticed the demon slayer mark on Su Chen's chest.
• Shinobu Kocho invited Su Chen to come with her, and he agreed to join the Demon Slayer Corps.
• Su Chen fainted into Shinobu Kocho's arms after overusing his comprehension.

After waking at the Ubuyashiki residence, Su Chen learned that Kagaya and the Hashira wanted to know about the marks on his body. He asked to join the Demon Slayer Corps, and Amane explained that his Demon Slayer Mark could herald a new golden age.

• Su Chen woke under Shinobu Kocho and Amane Ubuyashiki's care at the Master's residence.
• Kagaya Ubuyashiki arrived with the Hashira and asked Su Chen how he had awakened the patterned marks on his body.
• Su Chen asked to join the Demon Slayer Corps, and Kagaya offered him a Hashira position.
• Shinazugawa and Obanai Iguro objected to giving Su Chen the rank without the usual selection test.
• Amane explained the legend of the Demon Slayer Mark and revealed that Su Chen was the first person in their era to awaken one.

Su Chen explained the Demon Slayer Mark to the Hashira, and his own mark evolved as he spoke. After learning that awakening it could shorten their lives, the Hashira eagerly sought his help, but Sanemi challenged Su Chen’s suitability for a Hashira position, prompting Kagaya Ubuyashiki to propose a match in two months; Su Chen refused.

• Lady Amane asked Su Chen to explain how to awaken the Demon Slayer Mark, and he described its conditions and effects to the Hashira.
• As Su Chen explained the mark, he gained new insight, and it spread across his body before vanishing at his command.
• Su Chen told the Hashira that awakening the mark required facing near-death conditions and that marked swordsmen did not live past twenty-five.
• The Hashira accepted the risk and competed to invite Su Chen to their homes, hoping to learn from him.
• Sanemi argued that Su Chen had not proved his strength or resolve and should not receive a Hashira position without earning it.
• Kagaya Ubuyashiki proposed that Su Chen and Sanemi fight in two months, with Su Chen taking the selection examination if Sanemi remained unconvinced, but Su Chen refused.

Su Chen wagered that he could defeat Shinazugawa in half a month and earn a place as a Hashira-level member of the Demon Slayer Corps. He chose to stay at Shinobu Kocho's Butterfly Mansion, where she learned that his goal was to become stronger.

• Su Chen declared he could defeat Shinazugawa in half a month, and Kagaya Ubuyashiki set their fight for that time, with a victory earning Su Chen a Hashira-level position.
• After Kagaya Ubuyashiki and his wife left, Shinazugawa threatened to break Su Chen's bones, while the other Hashira invited Su Chen to stay with them.
• Su Chen chose Shinobu Kocho, who led him to the Butterfly Mansion as the other Hashira reacted with disappointment and jealousy.
• On the way, Shinobu Kocho asked why Su Chen wanted to join the Demon Slayer Corps, and he replied that he wanted to become stronger.
• Shinobu Kocho wondered whether Su Chen meant he might become a demon.

Su Chen arrived at the Butterfly Mansion with Shinobu Kocho to begin training and build his strength. After Shinobu was summoned to Headquarters, Aoi Kanzaki took Su Chen to see the training facilities, where three little girls suddenly ran up to them.

• Su Chen reassured Shinobu Kocho that he would not become a demon and explained that he wanted to learn from her and train at the Butterfly Mansion.
• Shinobu Kocho brought Su Chen into the Butterfly Mansion and introduced him to Aoi Kanzaki, who agreed to show him the training facilities.
• A black crow ordered Shinobu Kocho to report to Headquarters immediately, so she left on a mission.
• Aoi Kanzaki voiced her wish to help on dangerous missions, and Su Chen told her that managing the mansion already helped Shinobu.
• Su Chen followed Aoi Kanzaki toward the training facilities, observing the mansion's orderly grounds, when three little girls came running toward them.

Su Chen completed the Butterfly Mansion’s physical and reflex training, impressing Aoi Kanzaki enough that she arranged a stronger opponent for him. The next day, Su Chen faced Kanao Tsuyuri, who launched the first attack before the match officially began.

• Kiyo, Sumi, and Naho massaged Su Chen, and his coordination and flexibility improved as he endured the session.
• Su Chen beat Aoi Kanzaki in their medicinal-broth reflex match, so Aoi ended the training and promised to find him a new opponent.
• The next day, Su Chen met Kanao Tsuyuri, whom Aoi had brought in to challenge him.
• Kanao splashed medicinal broth at Su Chen before Aoi called the start of their match.

Su Chen matched Kanao Tsuyuri's reflexes in a medicine-cup contest, learned the Shadowless Hand skill, and won despite being splashed with broth. After passing the second stage, he followed Kanao to the courtyard as she began practicing swordsmanship.

• Kanao attacked Su Chen with cups of medicinal broth, but he dodged and gradually matched her speed by imitating her movements.
• Su Chen learned Shadowless Hand and used it to beat Kanao in the contest, though her delayed reaction splashed broth onto his face.
• Aoi Kanzaki confirmed Su Chen's victory, while Kiyo, Sumi, and Naho celebrated and asked whether he would become Shinobu's successor.
• Su Chen told the girls he was only staying temporarily, then considered how Shadowless Hand might work with a Nichirin Blade.
• After Aoi Kanzaki announced the third stage, Kanao left to practice swordsmanship in the courtyard, and Su Chen followed with a wooden sword.

Su Chen challenged Kanao Tsuyuri to a wooden-sword match and used his Heaven-Defying Comprehension to rapidly learn her movements and swordsmanship. When Kanao escalated to Flower Breathing, Fifth Form: Peonies of Futility, Su Chen copied the technique and took the same stance, with an Auspicious Cloud Pattern appearing on his neck.

• Su Chen practiced beside Kanao Tsuyuri, observed her movements, and quickly improved his swordplay.
• Su Chen asked Kanao to spar, and she attacked after he invited her to strike first.
• Su Chen learned Mastery of Footwork and Mastery of Swordsmanship while dodging Kanao's attacks.
• Kanao used Flower Breathing, Fifth Form: Peonies of Futility, and Su Chen replicated the technique through mental simulation.
• An Auspicious Cloud Pattern appeared on Su Chen's neck as he assumed Kanao's stance.

Su Chen defeated Kanao in a spar and used the match to encourage her to speak from her heart instead of relying on her coin. After he caught her Nichirin Blade between his fingers, Kanao felt her heart begin to awaken.

• Su Chen copied Kanao's Flower Breathing technique, defeated her in their spar, and asked why she had wanted to leave.
• Su Chen stopped Kanao from flipping her coin and encouraged her to say what she wanted; Kanao admitted she did not know how to talk.
• Su Chen proposed another strike as a game and offered Kanao her Nichirin Blade to use.
• Su Chen analyzed Kanao's attack, blocked it with a wooden sword, then caught her blade between his fingers when it cut through.
• Su Chen urged Kanao to listen to her heart, and his gentle praise made her feel her heart begin to beat again.

Su Chen reconciled with Kanao Tsuyuri and, by studying their earlier fight, learned and modified Flower Breathing. As he practiced on the Butterfly Mansion roof, Shinobu Kocho appeared beside him.

• Kanao Tsuyuri explained that she had left because she thought Su Chen did not need to take the third test, and Su Chen asked her to talk with him more.
• Kanao remembered Kanae Kocho and began opening up to Su Chen as he offered her guidance.
• Su Chen reviewed his fight with Kanao in his mind and used his observation and memory to learn Flower Breathing's techniques.
• Su Chen modified Flower Breathing to better suit his physique and decided to keep the name Flower Breathing.
• Shinobu Kocho surprised Su Chen on the Butterfly Mansion roof as he practiced.

Su Chen demonstrated Flower Breathing to Shinobu Kocho, who was reminded of her sister and impressed by his talent. After studying Shinobu’s unusual Nichirin Blade, Su Chen learned blade-design mastery and criticized the design, leaving Shinobu’s smile frozen.

• Shinobu Kocho recognized Su Chen’s breathing as Flower Breathing and learned that Kanao Tsuyuri had taught it to him.
• Shinobu asked Su Chen to demonstrate Flower Breathing, and he bargained for her to demonstrate Insect Breathing in return.
• Shinobu showed Su Chen her uniquely shaped Nichirin Blade and explained that it could not slash demons normally.
• Su Chen studied the blade, gained Nichirin Blade Design Mastery, and said he would have designed it differently.
• Shinobu’s smile froze when Su Chen criticized a blade designed by the chief of the Swordsmith Village.

Shinobu Kocho explained why her Insect Breathing relied on poison and demonstrated its techniques for Su Chen. As he watched and practiced, he comprehended Butterfly Footwork and improved his proficiency, while Shinobu finished her exhausting display.

• Shinobu Kocho told Su Chen that her lack of strength meant she could not decapitate demons, so she used poison, and Su Chen reassured her that her Insect Breathing was valuable.
• Shinobu Kocho demonstrated Butterfly Dance: Caprice, and Su Chen received a prompt saying he had comprehended Butterfly Footwork.
• Shinobu Kocho performed Dance of the Bee Sting: True Draw, and Su Chen earned the achievement A Small Test of Great Skill.
• Su Chen joined Shinobu Kocho in practicing her movements, and a prompt said his proficiency had increased.
• Shinobu Kocho demonstrated Dance of the Dragonfly: Compound Eye Hexagon and then her fastest, most demanding technique, Dance of the Centipede: Hundred-Legged Serpent's Belly.
• Shinobu Kocho stopped after the demonstration, flushed and trembling with exhaustion.

Su Chen mastered Insect Breathing, combined it with Flower Breathing, and brought Shinobu Kocho to tears by performing her sister’s sword techniques. The next morning, he began devising a new Breathing Style while Shinobu told Kagaya Ubuyashiki that Su Chen could control his Demon Slayer Mark.

• Su Chen comprehended Insect Breathing and combined its graceful techniques with Flower Breathing.
• Shinobu Kocho watched Su Chen perform Kanae’s sword techniques, remembered her sister, and thanked him through tears.
• Su Chen woke late, promised Kanao Tsuyuri he would practice with her later, and began reflecting on his skills.
• Su Chen analyzed the Dance of the Bee Sting and nearby bees for inspiration as he tried to create a new Breathing Style.
• Shinobu Kocho told Kagaya Ubuyashiki that Su Chen could control his Demon Slayer Mark, then said she had not awakened her own mark.

Kagaya Ubuyashiki learned that Su Chen had quickly mastered Insect and Flower Breathing and ordered Shinobu Kocho to bring him to the Hashira training grounds. Meanwhile, Shinazugawa and Obanai Iguro discussed Su Chen and sparred, and Shinobu returned to find Su Chen deep in thought at the Butterfly Mansion.

• Kagaya Ubuyashiki heard from Shinobu Kocho that Su Chen had learned Insect and Flower Breathing after seeing their techniques and asked her to take him to the Hashira training grounds when Kyojuro returned.
• Shinazugawa trained in the bamboo grove but still could not awaken his Demon Slayer Mark, and Obanai Iguro told him Su Chen had learned two Breathing Styles.
• Iguro urged Shinazugawa to teach Su Chen a lesson, then put off his mission to spar with him.
• Shinobu Kocho returned to the Butterfly Mansion and found Kanao Tsuyuri and the younger girls gathered around Su Chen as he sat beneath a tree.
• Kanao told Shinobu that Su Chen was thinking, and Shinobu wondered whether he was having another epiphany.

Su Chen demonstrated his self-created Bee Breathing to Shinobu Kocho after using its speed to evade her strike and touch her chin. Shinobu asked for a full demonstration, and Su Chen prepared to face her with the Seventh Form, Swift Lunge.

• Shinobu Kocho challenged Su Chen, but he dodged her attack with a sudden burst of speed and touched her chin.
• Su Chen explained that he had developed Bee Breathing, a variation of Insect Breathing inspired by bees’ wing vibrations, and named his first form Poison Stinger.
• Shinobu Kocho was stunned that Su Chen had created his own Breathing Style and asked him to demonstrate it fully.
• Su Chen borrowed a Nichirin Blade and asked Shinobu Kocho to be his opponent.
• Su Chen began using Bee Breathing’s Seventh Form, Swift Lunge.

Su Chen used his self-created Bee Breathing to defeat Shinobu Kocho in a sparring match, impressing her and the onlookers. Shinobu then told him that Kagaya Ubuyashiki wanted her to take him to the Hashira training grounds, and Su Chen accepted after teasing her.

• Su Chen used Bee Breathing to outmaneuver Shinobu Kocho and finish the spar with his blade at her neck.
• Aoi Kanzaki, Kanao Tsuyuri, and the three little girls watched in shock as Shinobu admitted defeat.
• Shinobu praised Su Chen's rapid improvement and recognized that he had reached Hashira-level strength in some respects.
• Shinobu relayed Kagaya Ubuyashiki's request for her to take Su Chen to the Hashira training grounds, and Su Chen looked forward to learning from the Hashira.
• Su Chen jokingly claimed he would refuse, prompting Shinobu to swing at him and miss.

Su Chen intensified his training at the Butterfly Mansion while Shinobu Kocho remained away on a demon-slaying mission, improving his physique and discovering a state he called Bullet Time. While looking for bandages in the basement, he found Shinobu Kocho’s laboratory and opened a notebook that appeared to be her diary.

• A crow ordered Shinobu Kocho to investigate a powerful demon on Autumn Sky Mountain, and she left after giving instructions to Aoi Kanzaki and Kanao Tsuyuri.
• After learning how hard Shinobu worked to care for the Butterfly Mansion and fight demons, Su Chen trained with Kanao Tsuyuri and learned the remaining Flower Breathing forms.
• Su Chen developed his physical conditioning and used meditation to enter Bullet Time, a state that heightened his perception and learning ability.
• With five days remaining before his duel with Shinazugawa, Su Chen helped Aoi Kanzaki treat patients, earning a reputation as a male miracle doctor.
• While searching the basement for bandages, Su Chen discovered Shinobu Kocho’s laboratory and opened a notebook that began, “Tuesday. Weather: sunny.”

Su Chen read Shinobu Kocho’s diary and learned how warmly she regarded him before worrying that her delayed return from a mission involving a powerful Lower Rank demon meant she was in danger. He borrowed Kanao Tsuyuri’s Nichirin Blade and promised to return to her.

• Su Chen read Shinobu Kocho’s diary, which described her growing affection for him and her plans to tell Oyakata-sama about his Bee Breathing.
• Su Chen read that Shinobu Kocho had gone to investigate a powerful Lower Rank demon on Autumn Sky Mountain, and he feared she might have encountered an Upper Rank demon.
• Kiyo searched Shinobu Kocho’s laboratory for Su Chen but found it empty.
• Su Chen entered Kanao Tsuyuri’s room and asked to borrow her Nichirin Blade so he could practice swordsmanship that night.
• Kanao Tsuyuri handed Su Chen her sword and showed concern, and Su Chen hugged her and told her to wait for his return.

Su Chen left the Butterfly Mansion at night to find Shinobu Kocho and test his strength, but lost his way before reaching Autumn Sky Mountain. An old man told him that Shinobu had been seen injured, and Su Chen faced a lurking presence in the forest.

• Kanao Tsuyuri gave Su Chen a jar of wisteria poison, and he thanked her before leaving the room.
• Su Chen secretly picked wisteria, coated his Nichirin Blade with poison, and departed the Butterfly Mansion after nightfall.
• Su Chen got lost while searching for Shinobu Kocho and stopped an old man to ask for directions to Autumn Sky Mountain.
• Su Chen paid the old man for information, and the man recalled seeing Shinobu among a group with blood on her sleeve.
• Su Chen warned the old man to leave the mountain, then stepped in front of him when rustling came from the forest and a pair of ferocious eyes appeared.

Su Chen defeated a demon on Autumn Sky Mountain and learned that Shinobu Kocho had gone uphill, where dozens of demons and possibly one of the Twelve Kizuki were waiting. He continued up the mountain and found another demon wounded by Shinobu Kocho’s poison, then attacked it.

• Su Chen sent the old man away and confronted a demon lurking in the darkness.
• Su Chen severed the demon’s limbs, tortured it into answering his questions, and learned that Shinobu Kocho had gone up the mountain.
• The demon revealed that there were dozens of demons uphill and possibly one of the Twelve Kizuki, so Su Chen killed it and continued climbing.
• Su Chen heard a wounded demon threatening Shinobu Kocho and recognized her poison on its left arm.
• The demon tried to eat Su Chen, and Su Chen drew his Nichirin Blade and appeared behind it to strike.