Lin Yi

Biodata

Feature	Details
Name	Lin Yi (林一)
Alias(es)	Lin Ichiro; Kamen Rider Joker; Knight; City Hunter of Kabukicho
Species/Race	Human; transmigrant
Gender	Male
Affiliation	Ichiro Trading; Tokyo Jujutsu High; temporary associate of Suguru Geto's faction
Occupation/Role	Private detective; urban hunter; Jujutsu High assistant supervisor (Window) in Shinjuku Ward
Status	Active
First Appearance	Chapter 1

Power Progression

Stage / Realm / Level	Chapter	Notes
Passive disguise state	4	Retains only trace cursed energy, masking him as an ordinary person; gains superhuman physical ability and sharpened instincts but cannot naturally see cursed spirits.
Sorcerer Form / “Emiya Superhero Form”	4 30	Converts physical attributes into enormous cursed-energy reserves; can reinforce himself and construct disposable cursed tools, weapons, and firearms.
Heavenly Tyrant state	6 10	Separates his body from cursed energy, gaining a vastly stronger physique, heightened senses, and high resistance or immunity to cursed-technique attacks.
Kamen Rider Joker armor / Knight form	10	Creates a soul-bound permanent cursed-tool suit with the Devour effect; it repairs itself by absorbing cursed energy and grants attribute feedback after kills.
Domain-countering combat application	23 24	While fully severed from cursed energy, a domain’s sure-hit effect cannot lock onto him; he later establishes immunity to cursed-energy damage from Grade 1 curses and below.
Black Flash Rider Punch	25 41	Learns that emotional fluctuations in Knight form facilitate Black Flash; determines an approximate one-in-three-punch trigger rate.
Future Sight	24 40	Develops a sixth-sense precognition ability that lets him anticipate attacks and evade before they land.
Mass attribute harvesting	50	Exorcises a cursed-spirit horde drawn by Sukuna’s Finger, receiving cumulative physical and cursed-energy growth through Devour.

Background / History

Lin Yi physically transmigrated into the world of Jujutsu Kaisen and acquired the innate cursed technique Polarity Reversal. Within three months, he established a legal identity as Lin Ichiro, opened the Shinjuku detective agency Ichiro Trading, and became an urban hunter operating around Kabukicho. Akutsu Chojuro, an underground boss whose life Lin Yi saved from a cursed spirit, helped him obtain his identity, agency, contacts, and early work. 2 36

Initially unregistered, Lin Yi took private jobs involving both criminals and curses. He was hired by Hiromi Higuruma to incapacitate yakuza witnesses, then attracted Tokyo Jujutsu High’s attention by leaving behind the declaration that he was a jujutsu sorcerer. 1

His confrontation with Nanako and Mimiko Hasaba brought him into contact with Suguru Geto. Although Lin Yi rejected Geto’s sorcerer-supremacist ideology, he entered a Binding Vow to help Geto collect designated cursed spirits in return for money and information. 8 12 15

After repeatedly crossing paths with Jujutsu High during cursed-spirit incidents, Lin Yi adopted the role of an ordinary civilian and eventually joined the school as an assistant supervisor in Shinjuku. He uses the position to observe the official jujutsu world while concealing his own identity and maintaining ties to Geto’s faction. 32 34

Lin Yi later recognized signs of Kenjaku’s interference in the creation of new sorcerers and chose to remain in Japan rather than flee. He became involved in protecting Yuko Takagi, testing himself against Rika Orimoto and other special-grade curses, and ultimately drew the attention of Satoru Gojo. 20 29 40 50

Appearance

In his ordinary identity, Lin Yi is a tall, strongly built man with a roguishly handsome appearance and a gaze that balances frivolity with seriousness. 1

• Around 185 centimeters tall. 1
• Short, slightly tousled dark-brown hair; sharp brows; deep-set eyes; high nose bridge. 1
• Usually wears a khaki trench coat over a red crew-neck shirt, slim black dress pants, and black leather ankle boots. 1
• Uses tactical goggles when working in his sorcerer form. 1
• His Knight form manifests as a black Kamen Rider Joker suit with crimson compound eyes. 40

Personality

Lin Yi is pragmatic, opportunistic, and strongly motivated by money. He treats supernatural work as a profession, negotiates fees directly, and uses his foreknowledge of future events to seek both profit and survival. 5 13 26

He is cautious around powerful opponents, particularly Satoru Gojo and Kenjaku, and frequently relies on disguises, misdirection, and carefully limited displays of power. 31 33 38

Despite his self-interested attitude, Lin Yi repeatedly protects others when they are in danger. He stays behind to draw off a curse user so Yuko can escape, saves her with a long-range attack, and pushes Yuta Okkotsu to better understand and use his power. 29 31 41

Lin Yi is also sarcastic and irreverent, especially toward Suguru Geto, whose ideology he openly ridicules. He nevertheless develops a degree of mutual trust with Geto’s group and enjoys the dramatic heroism of his Kamen Rider persona. 11 19 23

Abilities & Skills

Cursed Technique: Polarity Reversal

Lin Yi’s innate technique exchanges physical ability and cursed energy between two radically different combat states. Its passive state hides his nature as a sorcerer, allowing him to pass as an ordinary person. 4

• His disguised state leaves him with only trace cursed energy, making him difficult for sorcerers to identify. 4 12
• In exchange, he retains enhanced physical ability and instincts capable of sensing nearby cursed-energy activity. 4 5
• He cannot naturally see cursed spirits while in this state. 4

Sorcerer Form

By sacrificing his physical attributes, Lin Yi gains a massive cursed-energy reserve and becomes a conventional combat sorcerer. 4

• Reinforces his body with cursed energy for superhuman movement and striking power. 1 4
• Creates disposable weapons and tools from cursed energy, including blades, shields, firearms, grenades, binoculars, bows, arrows, and flying swords. 8 14 30 37 50
• Constructed items can carry chosen properties; after use, their cursed energy returns to him. 8
• His normal cursed-energy sensing radius reaches approximately fifteen kilometers and doubled to thirty kilometers after Technique Disclosure. 30
• Uses this range to deliver attacks beyond line of sight, including a Spiral Sword transformed into an arrow. 30 31

Heavenly Tyrant: Kamen Rider Form

Lin Yi’s second active state completely separates his body from cursed energy and manifests the Kamen Rider Joker suit as a permanent cursed tool. 10 21

• Possesses overwhelming physical strength, speed, durability, heightened senses, and a sixth sense. 10 24
• Is immune to cursed-energy attacks from Grade 1 cursed spirits and below; stronger attacks are mitigated according to their output. 24 31
• Cannot be targeted by a domain’s sure-hit effect while completely devoid of cursed energy. 23
• Can pass through barriers by exploiting the suit’s non-living, cursed-energy-less interaction with them. 10 15
• Lacks inherent killing power against curses when separated from the armor, as he cannot use cursed energy in this state. 24

Kamen Rider Joker Suit

The Kamen Rider Joker suit is a permanent cursed tool bound to Lin Yi’s body and soul. 10 21

• Repairs damage by absorbing cursed energy from the environment or attacks directed at it. 10 18
• Can be separated from Lin Yi and operated independently before merging with him again. 21 24
• Bears the Devour effect: killing cursed spirits or sorcerers grants Lin Yi 0.1% of their total attributes. 10 20
• Its accumulated attribute feedback strengthens both Lin Yi’s physique and cursed-energy capacity. 16 50

Rider Punch and Black Flash

Lin Yi’s signature close-range finisher is the Rider Punch, delivered through his Heavenly Tyrant physique and Kamen Rider armor. 18 25

• Defeated a newly born special-grade cursed spirit with a single Rider Punch. 18 19
• Can trigger Black Flash through the Rider Punch; a Black Flash-enhanced strike raises an attack’s power to the 2.5th power. 41
• Has used Black Flash through both punches and kicks. 41 50
• Powerful shouting and emotional fluctuation improve his chance of triggering Black Flash. 25 41

Future Sight

Lin Yi’s heightened instincts in Kamen Rider form develop into a precognitive combat sense. 24 40

• Produces brief future images that let him react before attacks are completed. 40
• Allows him to predict projectile trajectories and evade or intercept concentrated cursed-energy barrages. 24

Combat and Investigation

Lin Yi combines detective work, street-level connections, firearms, and supernatural combat ability. 2 30 46

• Uses surprise gunfire and suppressive fire effectively against curse users. 30 46
• Can exploit enemy technique disclosures and environmental resources, such as anesthetic cursed-spirit blood. 47
• Uses his assistant-supervisor identity to obtain information on cursed-spirit cases while concealing his true strength. 33 34

Equipment / Weapons / Items

• Kamen Rider W Hard-Boiled motorcycle — Modified from Lin Yi’s Honda CBR1000RR-R and later replaced after Geto compensated him for its destruction. 12
• Kamen Rider Joker suit — Soul-bound permanent cursed-tool armor with self-repair and Devour. 10
• Colt Python .357 Magnum revolver — Used in his ordinary identity for surprise attacks against curse users. 30 31
• M1911 semi-automatic pistol — A cursed-energy-infused firearm issued after he joined Jujutsu High. 34
• Cursed-energy detection sunglasses — Issued by Jujutsu High to detect cursed-energy fluctuations. 34
• Sukuna’s Finger — A special-grade cursed object Lin Yi uses to attract cursed spirits for mass exorcism and attribute harvesting. 50

Relationships

• Suguru Geto — Uneasy ally bound by a mutual Binding Vow; Lin Yi rejects Geto’s ideology but helps him subdue specific cursed spirits for compensation and information. Geto regards him as family. 11 12 19
• Kiyotaka Ijichi — Initially investigated Lin Yi as an unregistered sorcerer; later became his senior after Lin Yi joined Jujutsu High as an assistant supervisor. 1 33 34
• Kento Nanami — Suspicious of Lin Yi’s repeated involvement in curse incidents; Lin Yi has fought him while disguised as Kamen Rider Joker and later worked around him as Lin Ichiro. 19 20 33
• Nanako and Mimiko Hasaba — First attacked Lin Yi with their combined techniques; later became more accepting of him after his cooperation with Geto. 6 25
• Miguel O’Dwyer — Initially helped Geto corner Lin Yi; later assisted him during the attack on Yuko and came to respect his abilities. 9 30
• Larue — Fellow member of Geto’s faction who assists Lin Yi and learns part of his technique through Technique Disclosure. 30 31
• Yuko Takagi — A young sorcerer targeted by Kenjaku’s forces; Lin Yi protects her by acting as bait and killing her pursuer from long range. 29 31
• Yuta Okkotsu — Lin Yi battles Yuta and Rika to test himself while forcing Yuta to develop his cursed-energy control and Reversed Cursed Technique. 40 41
• Aoi Todo — Bonds with Lin Yi over their shared preferences at a Takada-chan handshake event; Todo sees him as a kindred spirit and potential mentor. 27
• Akutsu Chojuro — Kabukicho underground boss whom Lin Yi saved shortly after arriving in Japan; a friend and source of work contacts. 36
• Satoru Gojo — A powerful figure Lin Yi deliberately avoids until he can master higher-level techniques; they finally meet after Lin Yi’s mass exorcism in Nishitama District. 38 50

Story Role / Major Arcs

Unregistered City Hunter

Lin Yi begins as an independent Shinjuku urban hunter, handling yakuza, possession cases, and cursed-spirit incidents for money while hiding his sorcerer identity. His actions place him on Jujutsu High’s radar. 1 2 5

Geto’s Binding Vow

After overpowering Nanako and Mimiko and clashing with Miguel, Lin Yi enters a transactional alliance with Suguru Geto. He gains information, money, and access to powerful cursed spirits to test his evolving forms. 6 12 19

Lori Group Incident

Operating as Kamen Rider Joker, Lin Yi infiltrates the Lori Group building, destroys multiple cursed spirits, defeats a special-grade cursed spirit, and escapes with it before Jujutsu High can identify him. 15 16 18 19

Kenjaku’s Interference

Lin Yi identifies anomalies surrounding Yuko Takagi and suspects Kenjaku’s involvement. When a curse user targets Yuko, Lin Yi protects her while concealing his identity from Jujutsu High. 20 29 31

Double Agent at Jujutsu High

Using his civilian cover, Lin Yi becomes an assistant supervisor in Shinjuku. The position gives him access to official case information, though Jujutsu High continues monitoring him through a cursed corpse. 33 34

Elementary School and Rika Battle

Lin Yi collaborates with Geto to draw Gojo, Yuta, and Maki to an elementary school. He fights Rika Orimoto and deliberately pressures Yuta into using cursed energy and Reversed Cursed Technique. 37 40 41

Nishitama Cursed-Spirit Hunt

Using Sukuna’s Finger as bait, Lin Yi gathers and exorcises a large cursed-spirit horde to fuel Devour. The event ends with his first direct meeting with Satoru Gojo. 50

Notable Quotes

“As you can see, I’m a jujutsu sorcerer.” 1

“Come on, Cursed Spirit. Round three. Time to count your sins.” 23

“I still prefer the name Rider Punch.” 25

Trivia

• Lin Yi adopts the name Lin Ichiro after arriving in Japan and uses it for his legal and civilian identity. 2
• He chose Kamen Rider-style armor partly because cosplay is common enough in Tokyo to function as an inconspicuous disguise. 10
• Before joining Jujutsu High, he was classified in records as a suspected independently acting humanoid cursed corpse or cursed spirit under the codename Kamen Rider Joker. 15
• His stated long-term goals include mastering Reversed Cursed Technique and Domain Expansion. 4 13