KissXSis (2010)

Natsuo is a high school boy who is experiencing the crushing despair of unrequited love. To make matters worse, the person he is in love with is his teacher, Hina. In an attempt to lift his spirits, he attends a mixer where he meets a girl named Rui. The two sleep together, expecting never to see one another again, but fate has other plans. His 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: Hina and Rui!

Kinoshita Kazuya is a 20-year-old failure of a college student. He managed to kiss his girlfriend once, but was dumped after a month. Completely spiteful, Kazuya uses a certain method to date a girl. He goes to their meeting place and a beautiful girl brushing her long, black hair behind her ear was there, smiling at him. Her name was Mizuhara Chizuru. Something real is born after just a single rental! A reckless rom-com filled with love and excitement is about to begin!

Oreimo follows the daily life of an ordinary high school boy named Kyousuke Kousaka. Kyousuke’s younger sister Kirino is a pretty fashion model, but also hides a dark secret of being an otaku of adult games. Kyousuke is the only person to whom Kirino reveals her hidden obsession and other issues.

16-year-old Hayate is really down on his luck. Because his unemployed parents are good-for-nothings who waste what money they have on gambling, Hayate had to start working at a young age to help out his family. Although such experience has made him inhumanly fast and tough and skilled at things boys aren't normally skilled at, it has also left him in an awkward position, as his parents have racked up such a huge gambling debt that they have sold Hayate to the yakuza for the value of his organs. In a desperate attempt to avoid that fate, Hayate decides to become a "bad guy" and kidnap someone to be held for ransom, but his efforts to do so are mistaken as a confession of love by the girl he targets. When he helps save the (as it turns out) ultra-wealthy 13-year-old Nagi from real kidnappers, she takes him in and gives him a job as her new personal butler (and love interest) until he can pay off his debt. But Hayate is more attracted to Nagi's beautiful teenage maid Maria, and head butler Klaus is initially disapproving of a boy with such a poor look. And then there's Nagi's pet Tama, who is also a force to be reckoned with.

The story is about Rito Yuuki , a high-school boy who cannot confess to the girl of his dreams, Haruna Sairenji. One day when coming home and sulking in the bathtub a mysterious, nude girl, appears out of nowhere. Her name is Lala and she comes from the planet Deviluke, where she is the heir to the throne. Her father wants her to return to her home planet so she can marry one of the husband candidates, but she decides that she wants to marry Rito in order to stay on Earth.

Kasugano Haruka and his sister Sora have lost both their parents in an accident, and with them all their support. They decide to move out of the city to the rural town where they once spent summers with their late grandfather. At first everything seems familiar and peaceful, but changes come as Haruka starts to remember things from his youth.

For high school students like Shouichi Kamita, university entrance exams and the future are common concerns. It is also during this time in life that a mysterious emotion that vexes people of all ages may begin to weigh upon one's mind—love. At this point in his teenage years, Shouichi finds three girls he could see himself having a future with: the ever-cheerful Hikari Tsuneki, who teases Shouichi without mercy, but actually has a softer side; the competitive gamer, Tooru Miyamae, who has difficulty communicating with others; and Shouichi's childhood friend, Kyouko Touno, the sometimes immature shoujo manga enthusiast. Seiren follows Shouichi's relationships with these three girls across three separate arcs, as their feelings grow from mutual interest and blossom into something more beautiful.

Raku Ichijo is an average high school student. He also happens to be the sole heir to the head of a Yakuza Family called the Shuei-gumi. 10 years ago, Raku made a promise… a secret promise with a girl he met. They promised one another that they will “get married when they reunite.” Since then, Raku never let go of the pendant the girl gave him.

Ah, high school. Is there any better place to start fresh after a horrible middle school relationship? Nope! Not unless your ex ends up at the same school as you and is now your stepsibling. What was supposed to be a sanctuary of peace where I could avoid ever seeing her again has become a living nightmare! Everywhere I look, I see her—in my house, in my school, in my class. There's no escape! She even claims that she's the older sibling. Like hell she is! But I won't lose to her. After all, I'm the older brother in this new family situation. That's right, we're family now. No matter how much we may have thought we loved each other before, we saw one another's true colors and realized we weren't meant for each other. That's why even though we may keep up a buddy-buddy sibling act for the sake of our parents, things will never go back to the way they used to be.

Maiku Kamishiro grew up in an orphanage with no history of his family or of his past. Left with only a childhood picture of himself and another person in front of a house, he believes that the other person in the picture is his long lost twin sister. Upon discovering his old home, two young girls show up on his doorstep one day both claiming to be his long lost sister.