Mari Osano

Mari Osano is one of the protagonists of Sisters' Sexual Circumstances, and the protagonist of Mari's Sexual Circumstances.

Appearance
Mari is a woman in her mid 20s. She is pale, with dark brown hair accented with pale pink highlights, primarily in her bangs, and wears pink lipstick. In Sisters' Sexual Circumstances, she wears a blue floral-print dress with black underwear underneath, as well as a choker with a pink metal heart hanging off the front, and three ear piercings on either side. Her left ring finger is adorned with a wedding ring, and she wears a black anklet around her left ankle.

Mari's endings in Sisters' Sexual Circumstances depict her in a white maternity dress with pink and orange flowers on it, as well as silver-frame glasses, with a hair clip holding her bangs back.

In Mari's Sexual Circumstances, Mari wears a pink, tight-fitted tank top bearing the song title "Come Undone," with what appears to be a sample of the song's lyrics printed underneath, as well as navy blue lounge shorts, dark grey cloth stockings that expose her toes, a darker navy blue cloth headband, star-shaped earrings, and a choker with a crescent moon hanging off the front. Her fingernails and toenails are painted matte scarlet, and she retains her wedding ring from Sisters' Sexual Circumstances, as well.

Development images for Sisters' Sexual Circumstances featured two other floral-print dresses, one white with flowers of multiple colors (similar to her ending dress), the other black with white flowers. The initial test render for Mari's tank top in Mari's Sexual Circumstances featured the phrase "This is an original game of UMEMARO" underneath "Come Undone" rather than the lyrics the final model shows, and Mari's shorts were dark grey.

Traits
As a mature housewife, Mari is confident and self-assured throughout most of Sisters' Sexual Circumstances, contrasting with her immature, bratty younger sister. She is described in UMEMARO's recruitment posting for her voice actress as a "big sister type, calm, and eccentric." She is also shown to be willing to experiment sexually, demonstrated by her willingness to engage in foreplay with her own sister, and when she engages in sounding with the younger brother in her true ending. She seems generally content with her marriage, but is sexually frustrated, as her husband frequently falls asleep when she tries to initiate sex, or is out for long periods of time on business trips. This frustration has caused her loyalty to Kôji to weaken substantially, as evidenced by how quickly she consents to having an affair with his younger brother, particularly when he pleasures her successfully. Mari's sexual depravity is even more pronounced in Mari's Sexual Circumstances, where she is willing to drug a repair man in order to have sex with him, and engages in direct, willful netorare at Kôji's expense, calling him while she pleasures another man repeatedly. The only time she is shown to be timid or uncertain is at the very beginning of Sisters' Sexual Circumstances, when she is unable to get Kôji to have sex with her, feeding into the frustration that allows the younger brother to swoop in.

in Sisters' Sexual Circumstances
Mari is introduced in Sisters' Sexual Circumstances when her husband's younger brother witnesses her trying, and failing, to get her husband to have sex with her. When Kôji falls asleep, the younger brother sneaks into the room and has sex with Mari, eventually climaxing, either inside her or on her chest. If the younger brother climaxes inside of her, an alternate ending is shown where Mari, visibly pregnant with the younger brother's child, sees Kôji off to work.

In the true path, Mari slips the younger brother an aphrodisiac at breakfast the next morning, and she and Yuika pleasure him in various ways until he passes out. When he awakes, he sees Mari and Yuika engaging in foreplay, and, if Mari is chosen at this point, the younger brother has sex with her, climaxing inside her. Several months after this, Mari is shown to be visibly pregnant, engaging in sounding with the younger brother in the living room, after which Yuika accosts her upon returning home from school for doing such things in the living room of the apartment.

in Mari's Sexual Circumstances
In Mari's Sexual Circumstances, Mari seduces a repair man that has come to repair the air conditioning unit in her apartment. Serving him a snack and a drink, it is revealed that she has spiked his drink with an aphrodisiac, proceeding to tease and pleasure him when he develops an erection as a result while trying to repair the unit. Mari then proceeds to have sex with the repair man in a variety of poses and arrangements, giving him handjobs, blowjobs, footjobs, titjobs in addition to intercourse, occasionally calling her husband while she pleasures the repair man. After several rounds of sex, and a situation where Mari accidentally initiates a video call with her husband and has to act as if nothing is going on while the repair man has sex with her, the repair man takes control, having vaginal and anal sex with her until they are both satisfied.

The movie and game versions of the game provide several different epilogues. In the movie version, Mari is seen engaging in more anal sex with the repair man while she is on the phone with Kôji. In another ending in the game version, Mari is caught cheating by her husband, as he realized what was going on during the video call, but agrees to stay with her on the condition that she does not cheat again, something Mari promptly fails to do. The third ending occurs if the player is unable to successfully have anal sex with Mari during the final sequence of the game - Mari calls the maintenance company, requesting that they send someone to fix the water pipe in her home.

Development
Mari went through several changes during the development of Sisters' Sexual Circumstances. She was first seen on April 18, 2018, where UMEMARO stated that he was using Kayo Shinozaki's hair style as a placeholder on Mari's model. Two upper-body renders were shown in June 2018, revealing her full original design: a different face shape, a mole on the left side underneath her lower lip, black hair, three piercings in each ear, a different style of choker, a pink watch on her left wrist, and a white dress with flowers of multiple colors adorning it. This model was replaced in September 2018 by what ended up being Mari's final model, though the pink highlights were not added until September 25, and her dress was black with white flowers on it at this point, replaced by February 2019 with her final dress.

UMEMARO uncharacteristically allowed for fan input regarding Mari's new outfit in Mari's Sexual Circumstances. Klemmohazard, administrator of the UMEMARO 3D Discord server, reached out to UMEMARO to discuss potential changes to the color palette used, putting together a poll with eight color options for users of the Discord to choose from on December 13, 2019. Klemmohazard presented the top four voted options to UMEMARO for consideration, including the original color palette, which won by a margin of two votes. Reportedly, UMEMARO preferred the fourth-place palette, but ultimately chose to stick with the original color palette, as seen in the March 30 update, until changing the shorts color from dark grey to dark blue for the final release.

Trivia

 * Mari is 26 years old in Sisters' Sexual Circumstances, as stated in an internal recruitment posting for her voice actress.
 * Mari and Yuika 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, Mari and Yuika are the first characters shown to be married in the UMEMARO 3D canon.
 * Mari and Yuika 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.
 * Mari is the first female protagonist to appear in back-to-back releases since Chiha Rokuhato in Semen Analysis and Sugimoto Gynecology Clinic.