Yuuyuuko Amihara

Yuuyuuko Amihara (, Amihara Yūyūko), also known as Poltergeist, was a quirk user hired by the contract group the Agency, and assisted in missions using her quirk, Possess, to isolate and incapacitate single targets at long range.

Appearance
Yuyuko's appearance is of a relatively short, young woman, sporting brown pigtails and dressed in mechanic's overalls. Not being a fighter whatsoever, Yuyuko relied totally on other people to deal with enemy groups, but was able of spying and reconnaissance thanks to the chameleon properties of her quirk.

When she possessed Kumokyo Ichishi during The Sabotage, she functionally became her, assuming her direct appearance. She was not, however, privy to any of her memories or knowledge, resulting in her switch quickly being discovered by Nocturne.

Name
Her full name is Yuuyuuko Amihara. The characters for her given name Yuuyuuko (有々子) contain nen (有) which can mean possess, and ko (子), a common suffix for girls' names, meaning a child. The iteration mark "々", casually called a noma (ノマ), is used to indicate that the previous kanji should be repeated, functionally making her name equivalent to "有有子".

Her surname Amihara (亜美原) contains the characters a (亜), a "name kanji" used as the phonetic stand-in for the hiragana "あ", mi (美) meaning beauty, and hara (理) meaning a meadow or plain. Her surname means "beautiful plain".

Her name is a direct reference to the Touhou Project character Yuyuko Saigyouji, who possesses ghost-like qualities.

Personality
Yuyuko is quite cowardly and is never directly involved in combat or confrontation. Additionally, when she is confronted while possessing someone, Yuyuko tends to freeze up and panic instead of attempting to talk her way out of the situation.

Her inexperience ultimately resulted in her being left behind as bait for Nenneko Okorori and Rimou Yatsuhashi's retreat from the Organisation.

Quirk
Possess (幽霊 Yurei, ghost): Yuyuko's quirk allows her to swap her soul with the soul of another person she can "see". Upon switching, Yuyuko immediately takes full control of the other person's body, and the other person takes control of her body.

Possession is instant, but comes with caveats. The most important one is the fact that Yuyuko does not gain any of the possessed person's knowledge or memories, and thus she must entirely rely on previous knowledge and contextual clues to blend in with any enemies as an ally. Her "possession" also acts on a decent cooldown, preventing her from rapidly swapping back and forth between people. Possession does not immediately end if she is knocked out or killed, and killing Yuyuko's possessed body will also kill her, but also trap her target's soul in her body.

Additionally, Yuyuko is able to see the souls of other people within the radius of her quirk, which allows her to perceive the positions of sapient individuals at long range.