The story centers on Mizuto and Yume, a former couple who enjoyed a relationship in junior high school, but became more and more irritated at each other, and used their graduation as an opportunity to break up. But on the day before entering high school, the two reunite in the most unlikely way: with their parents announcing a marriage, with Mizuto and Yume now becoming step-siblings. Wanting to prioritize their parents' relationship, the two promise to not fool around with each other, establishing a rule where "the first one to get aroused" loses.
My Stepmom's Daughter is my Ex is finished and has 12 Episodes. It is also Known as: 継母の連れ子が元カノだった, Motokano, Tsurekano
Genres: Comedy, Romance, School Life, Shounen
Top 10 Anime Like Mamahaha no Tsurego ga Moto Kano datta
10. Ao Haru Ride

Futaba Yoshioka used to be an attractive and popular middle-schooler—well liked by the opposite sex, but ostracized by the girls. Nevertheless, she was able to brush all that off, because the only opinion that truly mattered to her was that of Kou Tanaka, a classmate with whom she shared a shelter from rain once, followed by quite a few other precious and significant memories. She even succeeded at making plans to meet with the quiet and innocent boy at the summer festival, but a simple misunderstanding, and Tanaka's subsequent disappearance, left her walking the halls of her school friendless.
Now in high school, Futaba is not your typical adolescent girl. Determined to become a class favorite this time, she avoids all unwanted attention and, instead of acting cute and feminine, only stands out through her tomboyish behavior and disheveled look. But still, her world is soon turned upside down when the only boy she ever liked unexpectedly comes into her life once again—except he goes by the name of Kou Mabuchi now, and it is not his name alone that has gone through a sea change.
Blue Spring Ride is finished and has 12 Episodes. It is also Known as: アオハライド, Aoharaido
9. Kiss x Sis (TV)

After Keita Suminoe's mother passed away, his father promptly remarried, introducing two step-sisters into Keita's life: twins Ako and Riko. But since their fateful first encounter, a surge of incestuous love for their younger brother overcame the girls, beginning a lifelong feud for his heart.
Now at the end of his middle school career, Keita studies fervently to be able to attend Ako and Riko's high school. While doing so however, he must resolve his conflicting feelings for his siblings and either reject or succumb to his sisters' intimate advances. Fortunately—or perhaps unfortunately for Keita—his sisters aren't the only women lusting after him, and there's no telling when the allure of temptation will get the better of the boy as well.
Kiss x Sis (TV) is finished and has 12 Episodes. It is also Known as: キスシス, Kiss x Sis (2010), Kissxsis
8. Domestic na Kanojo

Natsuo’s life suddenly becomes more complicated when his father comes home and announces he has remarried a woman with two daughters whom Natsuo has met before. They’re Hina, his teacher and unrequited crush, and Rui, a girl he previously slept with.
Domestic Girlfriend is finished and has 12 Episodes. It is also Known as: ドメスティックな彼女, Dome X Kano, DomeKano
7. Tokidoki Bosotto Russiago de Dereru Tonari no Alya-san

Alisa Mikhailovna Kujou is Seiren Private Academy’s “solitary princess.” She’s a half-Russian beauty with silver hair, at the top of her class, student council accountant, and…completely unapproachable. For some reason, she’s also taken on the responsibility of reprimanding the slacker who sits next to her in class. Masachika Kuze is constantly frustrating her by falling asleep, forgetting his textbooks, and just being an overall unexemplary student. Or at least, that’s how it looks from the outside. She may put on a tough act, but she doesn’t mind Masachika as much as others would think. She even lets him call her by her nickname, Alya. Anyone hearing the comments she mutters in Russian under her breath might know how she really feels, but since none of her classmates understand the language, she’s free to say whatever she likes! Except…there is one person who knows what she’s saying. Masachika eavesdrops on her embarrassing revelations, pretending to be clueless, all the while wondering what her flirtatious comments actually mean!
Alya Sometimes Hides Her Feelings in Russian is finished and has 12 Episodes. It is also Known as: 時々ボソッとロシア語でデレる隣のアーリャさん, Roshidere
6. Jaku-chara Tomozaki-kun

Tomozaki is one of the best gamers in Japan, and in his opinion, the game of real life is one of the worst. No clear-cut rules for success, horribly balanced, and nothing makes sense. But then he meets a gamer who's just as good as him, and she offers to teach him a few exploits...
Bottom-tier Character Tomozaki is finished and has 12 Episodes. It is also Known as: 弱キャラ友崎くん, The Low Tier Character "Tomozaki-kun", Jakusha Character Tomozaki-kun
5. Kiss x Sis

After his single father gets remarried, Keita Suminoe not only finds himself with a new mother, but also two beautiful twin step-sisters, Ako and Riko. Their close bond as children soon grows into something more personal, and Keita finds himself in a real bind that he vigorously struggles to escape from.
For the twins, the transition from little girls to teenagers brought about changes in appearance as well as emotional growth. Their love for Keita became something more than brotherly love, as they were both overcome with romantic feelings and pure lust. These innocent girls, being a couple of honest young ladies, could not help but confess their newborn love to their poor little brother. Hilarity ensues as Keita, who refuses to see the two as anything other than his sisters, then starts getting into embarrassing, sensual and lustful situations with them. Will Keita cross the line of incest or will he be able to protect his family jewels?
Kiss x Sis is an ecchi-filled harem anime that may make you blush a bit, but it will also surely make you laugh.
Kiss x Sis is finished and has 12 Episodes. It is also Known as: キス×シス, Kissxsis
4. Horimiya

Do opposites attract? At school, Hori is a social butterfly but her life at home is anything but perfect. Left to raise her brother, she’s facing responsibilities that she’s not ready for.
Meanwhile, under a brooding façade, Miyamura hides a gentle heart, along with piercings and tattoos. In a chance meeting, they both reveal a side they’ve never shown. Could this blossom into something new?
Horimiya is finished and has 13 Episodes. It is also Known as: ホリミヤ, Horimiya
3. Oniichan dakedo Ai sae Areba Kankeinai yo ne!

After six years of living separately, brother and sister Akiko and Akito Himenokouji are finally reunited. The two used to be quite close, until their parents died and they were sent to live with separate foster families. Now the two can live together and go to the same school as brother and extremely loving sister!
It doesn’t take long before it becomes abundantly clear that Akiko has a huge brother complex. Unfortunately for Akiko, her brother only sees her as a little sister he must protect. But that won’t stop her from trying to win her brother’s affections!
Things are only complicated when more girls move in with the siblings, making Akiko even more determined than ever to keep her brother’s eyes only on her. That’s tough to do with other girls flaunting their swimsuit-clad bodies at Akito, fighting over who gets to take care of him, and otherwise meddling in Akiko's plans for her brother. This is going to be one fun household…!
OniAi is finished and has 12 Episodes. It is also Known as: お兄ちゃんだけど愛さえあれば関係ないよねっ, As Long as There's Love, It Doesn't Matter If He Is My Brother, Right?
2. Gimai Seikatsu

From classmates to brother and sister, living under the same roof.
After his father's remarriage, Asamura Yuuta ends up getting a new stepsister, coincidentally the number one beauty of the school year, Ayase Saki. Having learned important values when it comes to man-woman relationships through the previous ones of their parents, they promise each other not to be too close, not to be too opposing, and to merely keep a vague and comfortable distance.
On one hand, Saki, who has worked in solitude for the sake of her family, doesn't know how to properly rely on others, whereas Yuta is unsure of how to really treat her. Standing on fairly equal ground, these two slowly learn the comfortable sensation of living together.
Their relationship slowly evolves from being strangers the more the days pass. Eventually, this could end up in a story about love for all we know.
Days with my Step Sister is finished and has 12 Episodes. It is also Known as: 義妹生活, Gimai Seikatsu
1. Omoi, Omoware, Furi, Furare

Yuna and Akari are two high school girls with very different views on love: Yuna dreams about romance through rose-coloured glasses, while Akari is down-to-earth and practical. Meanwhile, high school boys Kazuomi and Rio also have different views on love: Kazuomi is an airhead who can't grasp the concept of love, while Rio grabs onto any confession as an opportunity—so long as the girl looks cute. Will these four classmates end up leading a youthful romance that meets their expectations?
Love Me, Love Me Not is finished and has 1 Episodes. It is also Known as: 思い、思われ、ふり、ふられ, Love, Be Loved, Leave, Be Left, Furifura