Characters in Yui Kamio Lets Loose.
Tropes are split up to differentiate her two personalities and what they have in common. Black! and White! prefixes are for convenience.
- Alternate Identity Amnesia: Each of her personalities seems to not know what each other experiences to certain degrees.
- White!Yui doesn't remember what Black!Yui does yet Black!Yui was able to remember the promise White!Yui made with Kiito just a few moments before to keep his aspiration to be a veterinarian a secret.
- Black!Yui has no knowledge of what White!Yui has learned. White! knows English but Black! doesn't and her education stops at the 5th grade, the same timeframe of when the chain of Sanzo was first put on her.
- In-Series Nickname: Her personalities are called "Yui in Black" and "Yui in White".
- Secret Keeper: Is one for Kiito's desire to be a vet.
- She's Got Legs: She is tall with long beautiful legs
- Split Personality: When she was a kid, she got this when the monks sealed away her original personality.
- Split-Personality Makeover: When sealed, her hair is white. When she is let loose, her hair as well as the clothing she owns and wears, such as her white school uniform, turns black.
Black!Yui Kamio (Original personality)
- Boobs of Steel: She has big breasts and can kick butt.
- Chain Pain: Can use the loose chain of Sanzo as a binding weapon.
- The Gadfly/The Tease: Often acts like this to Kiito ever since he became a Secret Keeper.
- Reused Character Design: Her overall appearance is quite reminiscent of Hagoromo Gitsune's human form.
- Super Strength: She is so strong that she can carve through a stuffed toy bear with a swipe of her fist while still asleep.
- Wild Hair: She has this hairstyle. Design wise, it helps provides contrast to the black and white coloring of the manga and to further distinguish her from her White!Yui persona.
- Academic Athlete: She is both smart and physically fit.
- Hair Decorations: The chain of Sanzo. It not only ties her hair up it is also a Magical Accessory that ties down the Black!Yui personality.
- Helpless Good Side: Is slightly weaker and more passive than her Black! side.
- In-Series Nickname: In order to keep "Mai-Nyun" from learning that White!Yui is the same Yui Kamio she was looking for, Kiito gives White! the name "Mio-Nyun" to obstruct her.
- Proper Lady: How she is.
- Bishōnen: He is a handsome boy.
- Custom Uniform: He doesn't wear the uniform of Teiyo Private Academy and instead wears expensive clothes.
- Determinator: He is very persistent when he puts his mind to it.
- Secret Keeper: Becomes this when he learned of Yui Kamio's secret of having a split personality.
- Urban Legend Love Life: Despite his reputation of being The Casanova, he never had a real date alone with a girl before.
Teiyo Private Academy
A group of rich kids who lives life in "easy mode" since kindergarten.
- Childhood Friends: They are a group of them.
- Custom Uniform: They don't wear the uniform of Teiyo Private Academy.
- Rich Kids: They are rich kids who are high on life.
Kiito Sonomiya x Lady Koyagi Marriage Corps. (Kiito fan club)A group made to support Koyagi in marrying Kiito.
Kana's Special Agents
- Smoke Out: Uses a smoke grenade to disorient Kiito and Yui in order to try and get the latter's hair chain.
Guard Corps of Yui in Black
A group of girls who adore Yui in Black
- Ninja: Is a descendant of a ninja clan.
- Alpha Bitch: Was this when she was a kid.
- Attention Whore: Was this even as a kid.
- Bare Your Midriff: Her outfit by rolling up her shirt.
- Loves My Alter Ego: Likes "Mio-Nyun" (White!Yui) and views Yui Kamio as a bitter rival she wants revenge on while not knowing they are the same person.
- Modesty Shorts: Wears one under her skirt.
- Only Known by Their Nickname: "Mai-Nyun" is her In-Series Nickname, her real name is yet to be known.
- She's Got Legs
- Social Media Before Reason: During the climax of their rematch in chapter 4, as she had (Black!)Yui in a lock, she lets the spectators take some insta pics.
- Tomboyish Ponytail: Has one that hangs off the right side of her head.