Yuika

Yuika is one of the protagonists of Sisters' Sexual Circumstances.

Appearance
Yuika is a student who appears to be in her late teens. She has dark brown hair styled in a bob, accented with light brown highlights, and her ears are shown to be pierced, though she does not wear earrings. In the first half of Sisters' Sexual Circumstances, she wears a casual outfit consisting of a salmon-colored top with "All She Wants Is" written across the chest, a blue and white-striped thong, and thigh-high striped cloth stockings that expose her toes. In the second half and in Mari's true ending, she wears a schoolgirl uniform with a white top, blue flap collar, pink ribbon held in place with a white clip, blue skirt, and thigh-high striped nylon stockings that expose her toes. Yuika does not wear a bra with either outfit. She carries a white shoulder bag with a knockoff Nike logo ("Duke") in Mari's true ending.

Yuika's endings depict her in a white maternity dress with orange and pink flowers on it, as well as wearing a wedding ring on her left ring finger.

Traits
Befitting a high school girl, Yuika is loud and bratty. She is shown to be aggressive and assertive, though less sexually experienced than her older sister. Additionally, she is prone to loudly protesting when she believes that either the younger brother or her sister has wronged her, calling the offending party an idiot.

in Sisters' Sexual Circumstances
Yuika is introduced in Sisters' Sexual Circumstances when her brother-in-law witnesses her masturbating at her desk in her room. When the brother-in-law attempts to close the door, he makes a noise, alerting Yuika to his presence. The two proceed to masturbate together after Yuika confronts him, which eventually escalates to sex, ending in the brother-in-law climaxing either inside Yuika or on her face. If the brother-in-law climaxes inside her, an alternate ending is shown where Yuika, visibly pregnant with the brother-in-law's child, sits in her room with the brother-in-law - now her husband.

In the true path, Yuika slips the brother-in-law an aphrodisiac at breakfast the next morning, and she and Mari pleasure him in various ways until he passes out. When he awakes, he sees Yuika and Mari engaging in foreplay, and, if Yuika is chosen at this point, the brother-in-law has sex with her, climaxing inside her. Several months after this, Yuika is shown to be visibly pregnant, giving the brother-in-law - now her husband - a footjob in her room while she reads a magazine. Mari enters the room, speaking with Yuika for a moment before having sex with Yuika's husband as Yuika protests.

Trivia

 * Yuika and Mari Osano are the third set of sisters depicted in the UMEMARO 3D canon, following Kamira and Kurusu Kotara and Shizue and Yui Kori, and the first pair to not be twins.
 * Additionally, Yuika and Mari are the first characters shown to be married in the UMEMARO 3D canon.
 * Yuika and Mari are the first characters shown to be impregnated in an UMEMARO 3D release; a pregnant woman was previously featured in the background of a panel in Sugimoto Gynecology Clinic.
 * Yuika's surname was stated to be "Osano" during the development of Sisters' Sexual Circumstances, including in the internal casting call for her voice actress - however, in the final release's promotional material, she is referred to only as Yuika. Furthermore, Mari's husband in Mari's Sexual Circumstances is shown to have the surname "Osano" as well, implying that it is his family name rather than Mari and Yuika's.