[R +18] Kiss X Sis (2010)

Keita Suminoe is a third-year Japanese middle school student living with his father, stepmother, and older twin stepsisters, Ako and Riko. Since the remarriage of their parents at childhood, the siblings have always been affectionately close and supportive of one another. Picking up at least a decade later, the trio, now pubescent teenagers, see their opposites in a noticeably less platonic fashion; Ako and Riko frequently flirt and lust after Keita while, much to his chagrin, he fights the urge to give into them. The relentless admiration he receives, coupled with the situations and fan service that often ensues, is the primary basis of the series.

Characters:
Suminoe, Keita [Main] - Keita is a third-year junior-high school student studying for his high school entrance exams and although he is the younger brother, it is obvious he is the most mature of the three siblings. He wants to enter the same high school as his older twin step-sisters Ako and Riko, and to do so must study hard while getting help from his sisters as well as he was originally planning on relying on his track running scholarship for another school.

Suminoe, Ako [Main] - Ako is the elder twin sister. A way to tell her apart from Riko is that she wears a hair clip to keep the hair off her forehead. She has a reliable, level-headed personality, but can be sullen, moody, even a bit childish and is quickly embarrassed.

Suminoe, Riko [Main] - Riko is the younger twin sister. A way to tell her apart from Ako is that she wears her hair in a ponytail, and it is longer than her sister's hair. Also, she has a bandage below her left eye.

Mikuni, Miharu - A teenage girl that was introduced in chapter 18 where she returned Keita's acceptance letter when she found her dog trying to bury it in her yard. Out of a combination of stress from believing he did not get in to the relief he found out he did get in, Keita hugs her out of the blue. After that action she has shown an attraction towards Keita, often blushing when they talk and feeling very comfortable when he hugs her, but overall states she has nothing to do with him.

Kiryuu, Yuuzuki - She is Mikazuki's older sister, the new teacher to Gakushū Senior High and homeroom teacher to Keita and Miharu, who in an earlier chapter was a clothing store clerk because she liked western style clothing. Through bad timing and unaware that Keita and his sisters are not related by blood, she believes that he is a deviant who dates multiple girls while having an incestuous relationship with his sisters.

Kiryuu, Mikazuki - She is an underclassman that is "chasing after him (Keita)". They were in the same sports club back at his old school. She is even more perverted than Ako and Riko when it comes to getting Keita's attention, with no qualms of flashing her privates at him in front of others.