Yui Kamio is a legendary Japanese Delinquent who is considered the strongest and most violent in Japan. To address this, the monks, with the power of Sanzo Hoshi's chain, have forced a new personality of a "proper lady" upon her. Her Childhood Friend Nao Ebisuno is entrusted to keep the chain on Yui's head tied up, as she changes to her original persona without it.
Kiito Sonomiya is an arrogant rich boy and a School Idol of the Teiyo Private Academy. One day, after wanting to see a girl who'd be able to catch his interest, un-chained Yui crashes into him and beats him up, before being chained again by Nao. The chain makes Yui's clothing to visually change between "Yui in Black" and "Yui in White", with nobody being able to connect the two.
Trying to find his mysterious assailant, Kiito discovers Yui's secret and after witnessing that original Yui isn't so bad, he agrees to help Nao to keep her in check. And now Kiito has to deal with Yui in White being seen as his not-girlfriend, while Yui in Black's sheer reputation attracts bizarre and unnatural visitors to the Academy.
Yui Kamio Lets Loose (Kamio Yui wa Kami wo Yui) is a manga series by Hiroshi Shiibashi, which was serialized in Weekly Shonen Jump from March to November 2019.
Tropes in the series:
- All Girls Want Bad Boys: Despite Kiito being very cold to girls, they are excited to speak to him even as he dismisses them.
- Anticipatory Lipstick: In Chapter 11, Koyagi, the president of Kiito's fan club, uses drugged cookies to trick him into thinking she's Yui and puts on lipstick in an attempt to kiss to him, but is thwarted before she can plant it.
- Bait-and-Switch: Mushi grant superhuman powers while feeding on their victims acting out their worst fantasies. Yui is also said to already be possessed. Yui in Black is not one of them because Yui's Three Corpses and Nine Worms Mushi feeds on Yui holding herself back.
- The Beautiful Elite: The Life Lovers, a group of fabulously wealthy and privileged students whose life is a game on easy mode.
- Be Careful What You Wish For: In Chapter 1, Kiito wishes for a girl who could make an impression on him, and then moments later he meets Yui in Black who does so by punching and kicking him.
- Big Fancy House: Kiito's house is a rich large mansion.
- Bioweapon Beast: During WWII the Mushi were discovered by the Kitsujo family and bred to create an army of powerful women, but the research was lost when the war ended.
- Bland-Name Product: In the first chapter Life Lovers visit Moonbucks Coffee.
- Bound and Gagged: Yui gets kidnapped and tied up by Koyagi in Chapter 11.
- Catch a Falling Star: In Chapter 2, Kiito catches Yui in midair as she falls from the third floor of Teiyo Private Academy.
- Cerebus Retcon: Yui is known to have defeated every delinquent girl boss in the country, then was sealed becuase her personality was too violent. The second half of the series elaborates that "girl bosses" are specifically Mushi hosts chosen by Himiko, and Yui's sealment is implied to slow down the Mushi inside of her.
- Cerebus Syndrome: The series shifts from Romantic Comedy to Supernatural Horror at about the half-way point.
- Chekhov's Boomerang: The Yui in White's wig Kiito wore in Chapter 6 is used by Yui in Black to disguise as the other one in Chapter 9.
- Clark Kenting: Yui switching with another girl who looks exactly the same aside the color scheme doesn't clue anyone in that they are the same person, and she doesn't even hide her name.
- Cut Short: Since the manga was cancelled due to low popularity rankings, it ends by abruptly jumping to the epilogue with the Big Bad being defeated offscreen and her guardian stated to just suddenly disappear.
- Defeat Means Friendship: All the delinquent girls who Kiito removes the Mushi from end up in his friend group and assist in fighting other girl bosses. At least one of them seems to have a little crush.
- Demonic Possession: Mushi are supernatural hatred-fueled bugs that normally parasyte inside their host, though in Ayako's case the host is her violein. Chapter 28 shows a Mushi entering a host orally.
- The Dog Was the Mastermind: The person seemingly behind all the Mushi incidents is the young priest from the temple, though he's only cooperating with Hiniko.
- Duality Motif: Teiyo Private Academy's uniform has black and white checkerboard motif. Fitting for a new student with clothing-altering split personally.
- Elaborate University High: Teiyo Private Academy is an Elevator School at least goes from Kindergarten to High School. It also has a large sports field.
- Emotional Powers: Mushi abilities work when the victim expresses a specific feeling (fear for Honoka and peace for Ayako). Those who are emotionally prepared in advance don't get affected much.
- Evil All Along: The incompetent young monk has been conspiring with the Mushi the entire time.
- Fake-Out Make-Out: In Chapter 2, in order to give some trespassing delinquents the slip, Yui in Black grabs Kiito by the necklace chains he was wearing, pulls him close to her so that his body hides her from sight and puts a pen to his neck while their faces are close to each other which makes them look like a couple making out.
- Forgotten First Meeting: Yui in Black remembers the Guard Corps assisting her against Honoka two years ago, or specifically she recalls only that some two girls came out of nowhere and soon nearly died.
- Hilarity in Zoos: In Chapter 5, Kiito goes to the zoo to look at the animals and runs into Yui in White and Nao. Nao then excuses herself and it becomes a date between Kiito and Yui (with Nao sneakily watching them). It goes mostly well despite Kiito's awkwardness around Yui in White, a performance monkey stealss the Sanzo chain off of Yui and Yui in Black continues the date by dragging Kiito by the hand. Then a lion appeared due to the previous monkey stealing the key to its pen and unlocking it. Yui in Black subdues it and wants to take him home prompting Kiito and Nao to seal her back to Yui in White before she actually does so.
- Hyde Plays Jekyll: In Chapter 9 the chains get stolen, so Yui in Black has to go around in a white wig in case someone may be watching on her. Kiito figures her out right away because Yui in White would never beat a random civilian and has to cover up her mistakes in school.
- Immortality Inducer: Having a Mushi lets the host stay alive and regenerate even if chopped into pieces.
- In-Series Nickname: Everyone in the Academy thinks Yui in White is an angel and Kiito specifically asks if he can call her that, which she denies. Ironically, Yui in Black is known as The Devil.
- Interrupted Suicide: In Chapter 9, Yui Kamio (Yui in Black disguised as Yui in White) stops a would-be suicide in the train station and was beating him up for it and his subsequent attempts.
- Japanese Delinquents:
- Yui, prior to her black self's sealing with the Sanzo Chains, had conquered every delinquent gang in the country.
- Half of the early chapters feature bullies hunting Yui looking for revenge. And all the later chapters are about superpowered girl delinquents hunting down Yui Kamio.
- Knight of Cerebus: Honoka showing up changes the premise from a Slice of Life comedy to an Action Horror plot about creatures called Mushi that grant people incredible strength and drive them to act on their hidden desires.
- Leaning on the Fourth Wall: In Chapter 15 Kiito asks if they're going to do another Boob Based Gags or not, expecting Yui to hug him.
- Money to Throw Away: In Chapter 7, Kiito throws some money to distract the students in the school's indoor basketball court as he chases Yui in Black, who was running around in a Navel-Deep Neckline swim parka.
- More than Mind Control: Despite Mushi being parasites who enhance the hatred, Mushi hosts are shown to generally understand what they are and use them for their serial killings. Sealing the Mushi also doesn't fully solve the problem if the host desires it back. Even Kara who was forcibly possessed is more of an exaggeration of her inner desires.
- Nosebleed: In Chapter 7, Nao gets a bloody nose when she sees Yui in White get a Sexy Soaked Shirt with her white uniform as they were cleaning the pool. Later that chapter, Kiito gets another one when he sees Yui's white panties.
- Parasol of Prettiness: In Chapter 5, Yui in White has a white umbrella while she was visiting the zoo. It changes into black when she turns into Yui in Black.
- The Pollyanna: Yui in White is all the positive aspects of Yui Kamio distilled and rarely has negative thoughts. Subverted in Chapter 14 when Yui reveals she's depressed and would prefer to have Yui in Black's confidence and attitude.
- Pool Scene: Chapter 27 shows the entire cast taking a break on Kiito's yacht.
- Porn Stash: Ebi suggests the gang to study at Kiito's place, specifically to find any dirty stuff in his room that would make him unworthy of Yui. Turns out his embarrassing secret is a collection of books on building popularity.
- P.O.V. Boy, Poster Girl: The protagonists are Kiito, a simple rich boy who doesn't really get what's going on, and eponymous Yui who drives the story.
- Product Placement:
- In chapter 6, GRAVITY INDUSTRIES' "Iron Man Suit" that was sold by SELFRIDGES was shown in the possession of Kiito, which implies that he or his family bought it In-Universe.
- In chapter 10, Yui in Black, Kiito and Garasha play Twister.
- Pun: One of Kiito's thoughts about Yui if the chains are making her "chain-ge".
- Pun-Based Title: The title references the protagonist Yui Kamio and what happens when her hair is let loose Explanation In the Japanese title, "Kami" also can mean "hair".
- Roofhopping: When Kiito chases Ayako, he jumps to the roof of the next building. Despite regular exercises, he's still a Muggle and strains his ankle.
- Sexy Soaked Shirt: In Chapter 7, both Nao and Yui in White have their white uniforms get wet during pool cleaning, and Nao is sent to the nurse's office after Nosebleeding.
- Shared Universe: Shares continuity with Nura: Rise of the Yokai Clan as Ryuji Keikain appears at Yui's behest in Chapter 14.
- Shout-Out:
- The chain of Sanzo that binds Yui is the golden fillet of obedience that was used on Son Goku in Journey to the West.
- In chapter 1, when the gang leader remembers how Yui beat him and his gang back in 5th grade, the encounter is depicted as one to original Gen 1 Pokémon wild encounters.
- Kiito calls Koyagi Doctor Strange for her use of Instant Runes. Turns out it's her actual nickname due to her brewing potions.
- Shower Scene: In Chapter 8, there were two shower shots the first featuring Kiito and the second was with Yui in White.
- Skewed Priorities: In the second chapter Kiito goes to find loose Yui in Black, mainly because she's now viewed as his girlfriend and he has a reputation to fix.
- Sorting Algorithm of Evil: The series goes from oddball fans, to people who actually threaten Yui and Kiito, to actual monsters.
- Talking the Monster to Death: Kiito, a normal person, wins against a Mushi host Ayako by poking holes in her morality.
- Tarot Troubles: Ryuji gives Yui a reading on Oracle Harikikigaki cards, each displaying a Mushi representing her past, present, and the future, with the last one appearing monstrous to her, despite actually being blank.
- That Came Out Wrong: In Chapter 8 Kiito asks Yui in Black, who is running around in a bathrobe, to come to the locker room with him (so he can tie her hair). She naturally responds by running away.
- Two-Person Love Triangle: Kiito falls in love with both Yuis, the White one for being a sweetheart and the Black one for bringing excitement to his life.
- Upper-Class Twit: Kiito starts off as a rich boy who looks down on others except his friends Life Lovers. Him meeting Yui gradually turns his character for the better.
- Vapor Wear: In Chapter 7, Yui in Black goes about Teiyo Private Academy in a partially zipped swimming parka and black thigh high socks due to getting her clothes wet while as Yui in White. It gives her a Navel-Deep Neckline showing that she isn't wearing a bra. Yui in Black teases Kiito into wondering whether or not she was wearing panties. After Kiito finally corners her, she relents and gives a Panty Shot to him to show that she was properly wearing panties.
