Koji Osano

Kôji Osano is a minor character in Sisters' Sexual Circumstances and its sequel Mari's Sexual Circumstances, the husband of Mari Osano.

Appearance
Kôji is a man that appears to be in his forties, with prominent lips and deeply tanned skin. His hair is styled in a kind of mohawk, with the sides of his head shaved bald, and a large patch of brown hair running down the middle. He is always seen in a typical two-piece suit and tie, and carries a briefcase, as seen in Mari's bad end in Sisters' Sexual Circumstances.

Traits
As Kôji is not prominently featured in either of his appearances, not much is known about his personality. He is a typically hard-working Japanese businessman, working long hours and frequently going on days-long business trips, which often results in him being too tired to engage with Mari on a sexual level. This is clearly demonstrated in Sisters' Sexual Circumstances, where he falls asleep while Mari is attempting to pleasure him, and does not wake up even when his younger brother sneaks in and has sex with Mari right next to him. Yuika is not fond of him, disparaging the way he seems to prioritize work over his home life, and though Mari is defensive of him in this circumstance, she is not above cheating on him to fulfill her needs. On this front, he seems to be a little clueless, as Mari talks with him on the phone several times while cheating on him, at one point even engaging in a video call, leaving him none the wiser.

in Sisters' Sexual Circumstances
Kôji is first referenced in the audio the plays over the main menu of Sisters' Sexual Circumstances, where Mari and Yuika discuss his work habits and lack of attention paid to Mari. Later, in Chapter Mari, he is shown lying in bed with Mari, who is desperately attempting to get him in the mood for sex. Kôji, however, ends up falling asleep before Mari can get him ready, and he remains asleep while his younger brother sneaks into the room and has sex with Mari. He is last seen in Mari's bad end, heading off to work while Mari watches, unaware that she is pregnant with his brother's child.

in Mari's Sexual Circumstances
Kôji is featured more prominently in Mari's Sexual Circumstances, appearing twice in voice-only form and once via video call. Mari calls him while giving the air conditioning repair man a hand job, engaging in light conversation with him and leaving him none the wiser. He calls her back later while she is having sex with the repair man, startling her and causing her to accidentally accept a video call. They talk while Mari continues to have sex, holding the phone close to her face and waving off Kôji's suspicions, during which he is either completely unaware, suspicious, or discovers the truth, only to be hung up on. At the end of the movie version, he is last heard from speaking with Mari over the phone again, while she is once again engaging in sex with the repair man.

Trivia

 * Kôji is the first male character shown to be married in the UMEMARO 3D canon.