Biodata
| Feature | Information |
|---|---|
| Name | Lei Sai (雷赛) |
| Gender | Male |
| Affiliation | Demon Slayer Bureau; Qin Yuan's team; Lei Family of Qinghe Prefecture 62 86 |
| Occupation/Role | Third-Class Demon-Seeking Captain; archer, movement-technique specialist, and demon tracker |
| Cultivation | Early Condensing Qi Realm 62 168 |
| Family | Lei Family patriarch (father); Lei Jiaojiao (older sister); Lei Xing (great-aunt) 49 166 253 |
| First Appearance | Chapter 47 |
Power Progression
| Chapter(s) | Development |
|---|---|
| 62 | Introduced as an early Condensing Qi Realm Third-Class Demon-Seeking Captain specializing in movement techniques, longbow use, topography, and demon tracking. 62 |
| 85 | Remains below middle Condensing Qi despite access to high-grade medicinal herbs and premium martial arts; Lei Jiaojiao contrasts his progress with Mu Yang's rapid advancement. 85 |
| 168 | His early Condensing Qi cultivation is reaffirmed before the Blessed Land Grand Selection; his archery is acknowledged to require adequate distance and time to draw and nock arrows. He is also subjected to harsh underwater training by Lei Jiaojiao and Lei Xing. 168 |
| 175 | Participates in the fourth-tier division of the Blessed Land Grand Selection but is declared defeated following a rules violation. The violation consists of entering Zhou Yao's match without authorization to protect her from Ji Bucheng, rather than misconduct during his own scheduled match. 175 |
Background / History
Before joining Qin Yuan's Demon Slayer Bureau team, Lei Sai pursued suspected demon activity involving a Pingwei Escort Agency convoy carrying Su Wanqing. He blocked the convoy after identifying a possible demon threat, but the escorts dismissed his suspicions and attempted to force him aside. 47 48 After Mu Yang killed the demon and killed Su Wanqing, Lei Sai questioned whether she should have been killed, beginning his recurring attempts to understand Mu Yang's uncompromising judgments. 49
His suspicion of the convoy was supported by a Demon-Seeking Compass, whose needle pointed toward Su Wanqing's carriage. He offered to apologize personally if his judgment proved mistaken, but refused to abandon the investigation merely because the escorts invoked their agency's authority. After Mu Yang departed, Lei Jiaojiao challenged the reasoning that had persuaded Lei Sai to accept Su Wanqing's death. Su Hai subsequently learned that Lei Sai had been the one to stop his daughter's carriage. 47 49 51
Lei Sai was already a member of Qin Yuan's Demon Slayer Bureau team when Mu Yang and Ma Xuan were assigned to it. He recognized Mu Yang from their previous encounter with Su Wanqing's convoy. His bureau role combines movement techniques, longbow use, demon tracking, and a secondary knowledge of topography. 62
During the investigation of demon collusion in Wu Family Village, he and Mu Yang were tasked with collecting the informant Yue Miao. Lei Sai was troubled by the moral question of whether Su Wanqing deserved to die, while Mu Yang refused to entertain the dilemma. 63 He treated Yue Miao gently, explained their assignment, and invited her to address him by name rather than as an officer. 64 He later participated in the investigation of Yue Miao alongside Mu Yang and Zhou Yao. 68
Following the Zhimeng incident, Qin Yuan warned the team not to let sympathy for an exceptional demon lead them to spare other monsters and endanger their companions. That night, while sharing a room with Mu Yang, Lei Sai remained unable to sleep and asked whether Mu Yang would have killed Zhimeng if she had neither gone mad nor eaten anyone. 74
During an outing with Lei Jiaojiao and Mei Cao, Lei Sai unsuccessfully sought Mu Yang's company as relief from their teasing. The three subsequently followed Mu Yang out of the city and watched his confrontation at Su Family Manor from a rooftop. When Lei Jiaojiao tested his judgment about whether the manor's master deserved death, Lei Sai answered decisively but justified his answer simply by saying that Mu Yang had acted. After Mu Yang detected them, Lei Sai reluctantly accepted his sister's claim that following him had been Lei Sai's idea and apologized. 80 81 85 86
After the Wedding Dress Woman's defeat, Lei Jiaojiao woke Lei Sai to lecture him about the incident. His question about her own contribution embarrassed her, resulting in a forced sparring session from the hour of the Rat until dawn. He later recounted Mu Yang's victory enthusiastically to Zhou Yao while omitting his own punishment. 102
At Linhe Village, he supported Qin Yuan's team during the pursuit of a black-clad kidnapper and the appearance of the Drowned Corpse. He used his arrows to contain the black-clad man and employed the Demon-Seeking Compass to confirm that demonic energy was concentrated near the river. 108
During this period, Bao Tian also targeted Lei Sai for revenge. Angered that the Lei Family had protected Mu Yang after Bao Ping's death, Bao Tian intended to make the family experience the loss of a child. 103
After seeing Mu Yang defeat a Tier 5 Catfish Minion underwater without needing to breathe, Lei Sai was impressed and resolved to train harder. 113 However, Mu Yang's subsequent defeat of Bao Tian left Lei Sai and the rest of the team shocked and wary. 116
Lei Sai continued meeting Mu Yang after the latter advanced beyond Qin Yuan's squad, including sharing breakfast with him and Zhou Yao. When Mu Yang selected a Meridian Clearing Method, Lei Sai initially assumed he was preparing for a future breakthrough and estimated that even Mu Yang might require a year or two to reach the Channel-Opening Realm. Learning that Mu Yang had already become a First-Class Demon-Seeking Captain left him stunned. 123 125
During the Blessed Land Grand Selection, Lei Sai became furious at Ji Bucheng's deliberate humiliation of Zhou Yao. When Ji Bucheng aimed a potentially permanently damaging blow at her chest, Lei Sai entered the arena and took the hit to protect her. His unauthorized intervention resulted in his own scheduled match being declared a defeat, awarding another victory to the Six Fan Gate. Lei Sai accepted the punishment without objection. 175
Following the Blessed Land Grand Selection, a clan marriage arrangement originally intended for Lei Jiaojiao and Mei Cao was redirected toward Lei Sai and a direct-descendant daughter of the Mei Family. His inability to oppose the arrangement caused Zhou Yao to avoid him and left him deeply despondent. 252 Mu Yang later accompanied him to the Lei Family estate, where the Lei Family patriarch agreed that Lei Sai should decide his own marriage. 253
Lei Sai was bewildered that Mu Yang had resolved the dispute with so little discussion after his own prolonged appeals had failed. Lei Jiaojiao explained that Mu Yang's reputation and Sixth Rank strength made their father unwilling to oppose him, and reminded Lei Sai to inform Zhou Yao of the decision. 253
Personality
Lei Sai is conscientious and prone to reflecting on difficult judgments, particularly when human wrongdoing and demon-related killings overlap. His tendency to dwell on such questions frustrates Mu Yang. 63
His sense of duty is grounded in his reading of the Great Jing Records. He regards demon slaying as a martial artist's responsibility and is especially indignant toward humans who collude with demons. His initial confrontation with the Pingwei Escort Agency demonstrates his willingness to persist despite intimidation, while his treatment of Yue Miao shows consideration toward ordinary people. 47 63 64
He is sociable with his teammates and maintains a friendly rivalry with Zhou Yao. 62 102 He admires Mu Yang's rapid progress, though it regularly leaves him incredulous. 102 125
His admiration can become uncritical reliance on Mu Yang's judgment. At Su Family Manor, he confidently declares that the manor's master deserved death because Mu Yang had taken action, disappointing Lei Jiaojiao's hope that he had learned to reason independently. 85
Lei Sai is protective of Zhou Yao and becomes furious when Ji Bucheng deliberately humiliates her during the Blessed Land Grand Selection. 175 He prioritizes her safety over his own participation, accepting disqualification after intervening to shield her. 175 Despite his competitive spirit, he is self-conscious about his own talent and limited potential when compared with Mu Yang. 258
Around his family, Lei Sai is notably compliant with his sister Lei Jiaojiao and apprehensive of Lei Xing. 86 166 He wants to prove himself in the Blessed Land Grand Selection, but his early Condensing Qi cultivation and the practical demands of archery limit his confidence. 168
His marriage dispute exposes his difficulty understanding how strength and reputation affect family authority. He initially cannot comprehend why his father's refusal disappears as soon as Mu Yang visits. 253
Abilities & Skills
Longbow Archery
Lei Sai specializes in the longbow as part of his Demon Slayer Bureau role. 62
- Demonstrated alertness and archery skill during the Linhe Village confrontation, where he held a black-clad opponent at bay with arrows. 108
- His effectiveness depends on having sufficient space and time to draw and nock arrows. 168
Movement Techniques
Lei Sai specializes in movement techniques. 62
- Uses mobility as a core part of his combat specialization.
- His early Condensing Qi cultivation is documented during the period before the Blessed Land Grand Selection. 168
Demon Tracking
Lei Sai excels at tracking demons. 62
- Carries and uses a Demon-Seeking Compass in the field.
- His compass was forged by the Demon Slayer Bureau's Heavenly Crafts Hall and can locate monsters within a one-li radius. He used its reading as evidence when stopping Su Wanqing's carriage. 47
- Used the compass at Linhe Village to identify demonic energy emanating from the river. 108
Topography
Lei Sai has secondary expertise in topography. 62
- Provides terrain-related specialization within Qin Yuan's team.
- Reflects the bureau principle that teammates cover one another's blind spots. 102
Relationships
- Mu Yang — Former teammate and friend. Lei Sai first encountered Mu Yang while investigating Su Wanqing's escort convoy, then later served beside him in the Demon Slayer Bureau. He is repeatedly astonished by Mu Yang's advancement and combat strength; Mu Yang also intervenes to help him resolve his marriage dispute. Their friendship continues after Mu Yang's promotion takes him out of Qin Yuan's squad. 47 49 62 113 123 125 253
- Qin Yuan — Team leader in the Demon Slayer Bureau. He cautions Lei Sai against misplaced mercy toward demons and encourages him to recognize the effort behind Mu Yang's apparent accomplishments. 62 74 113
- Zhou Yao — Teammate, friendly rival, and romantic interest. They engage in playful banter and compete over their Blessed Land Grand Selection performances. Lei Sai is distressed when an arranged marriage causes her to avoid him, and later speaks openly of their hoped-for future child. They grew up together, and his intervention against Ji Bucheng brings their affection into clearer view. 62 102 174 175 252 258
- Lei Jiaojiao — Older sister. He is obedient to her wishes but becomes the target of her retaliatory “training,” including an enforced five-li underwater swim. She later feels guilty over the marriage arrangement imposed on him. She also challenges his moral reasoning and explains the role of Mu Yang's strength in resolving his marriage dispute. 49 80 85 86 168 252 253
- Lei Xing — His great-aunt, the older sister of Lei Sai's grandfather and a powerful elderly martial artist who appears as a little girl through an appearance-preserving cultivation technique. She is the Water-Splitting Sect's Supreme Elder and a sixth-rank Aperture-Opening Realm martial artist. Lei Sai is hesitant to disclose her identity and is subjected to her harsh training. 166 168 191
- Mei Cao — Acquaintance and companion of Lei Sai and Lei Jiaojiao. Mei Cao's refusal of the planned marriage alliance with Lei Jiaojiao contributed to the arrangement being redirected toward Lei Sai. Lei Sai grew up hearing Mei Cao held up as a role model, but also finds that Mei Cao cooperates readily with Lei Jiaojiao in teasing him. 80 85 86 252
- Lei Family Patriarch — Lei Sai's father, who initially upheld the arranged marriage but later permitted Lei Sai to decide his own marriage after Mu Yang's visit. 252 253
- Bao Tian — Enemy who targeted Lei Sai to retaliate against the Lei Family for protecting Mu Yang after Bao Ping's death. 103
Story Role / Major Arcs
- Su Wanqing escort convoy incident — Pursues a suspected demon concealed within Su Wanqing's convoy, crosses paths with Mu Yang, and begins questioning Mu Yang's standards for judging demon collaborators. 47 49
- Demon Slayer Bureau recruitment — Introduced as a Third-Class Demon-Seeking Captain in Qin Yuan's team after Mu Yang joins the bureau. 62
- Wu Family Village investigation — Accompanies Mu Yang to retrieve Yue Miao and later investigates her apparent circumstances with Mu Yang and Zhou Yao. The Zhimeng incident prompts further questions about whether a demon that has not harmed humans should be killed. 63 64 68 74
- Su Family Manor confrontation — Watches Mu Yang's battle alongside Lei Jiaojiao and Mei Cao, demonstrates his growing reliance on Mu Yang's judgment, and apologizes after their observation is exposed. 81 85 86
- Linhe Village / Water Transport Gang case — Supports Qin Yuan's team at the river confrontation, uses the Demon-Seeking Compass to detect demonic energy, and later witnesses Mu Yang's underwater defeat of the Catfish Minion. 108 113
- Aftermath of Bao Tian's defeat — Is shaken by Mu Yang's overwhelming display of strength. 116
- Lei family training — After becoming drunk at Jixiang Restaurant, he is taken home by Mu Yang and forced into harsh river training by Lei Jiaojiao and Lei Xing. 168
- Blessed Land Grand Selection — Participates in the fourth-tier division, wagers competitively with Zhou Yao over who will last longer, and is later disqualified following a rules violation. His unauthorized intervention protects Zhou Yao from Ji Bucheng's attack but costs him his own scheduled match. 174 175
- Marriage dispute — Is assigned a political marriage with a Mei Family direct descendant, causing conflict with Zhou Yao, before Mu Yang helps secure the Lei Family patriarch's approval for Lei Sai to choose his own marriage. 252 253
Trivia
- Lei Sai drank the most during the Jixiang Restaurant gathering and was too intoxicated to return home unaided. 168
- His sister ordered him to swim five li underwater and return while holding his breath; failure meant he would not be allowed home. 168
- While enduring the training outside the city, he suffered an exceptionally terrifying nightmare. 168
- He repeatedly asks Mu Yang to explain difficult matters, only to be told to “figure it out” himself. 74 113 253
- Lei Jiaojiao and Mei Cao regularly brought him along on outings to ease the awkwardness of their own unwanted marriage arrangement, then entertained themselves by teasing him. 80
- After asking what Lei Jiaojiao had contributed to the Wedding Dress Woman battle, he was made to spar until dawn and spent most of the following day recovering in bed. 102
- Before learning of Mu Yang's actual promotion, he considered opening his own first major meridian within ten years a respectable achievement for his talent. 125
- His Blessed Land Grand Selection registration number was fourteen. His scheduled opponent belonged to the Six Fan Gate and received victory by default after Lei Sai's rules violation. 175