Learning the Hard Way (2007)

This is the story of a boy, who became the lone Adam among four billion Eves. In a world where a pandemic has rendered all men impotent, high school student Itsuki is the exception who escaped it. In order to protect this secret, he transfers to a very special high school, which turns out to be composed of 90% girls! There, he encounters an upbeat and friendly senior, a sexually frustrated female teacher, a tomboyish school 'prince,' and an heiress from a wealthy family. For Itsuki, who has his pick of any woman in the world, the question remains: which one will he choose?

When Mafuyu Oribe and her adopted sister Tomo rescue a strange wounded man, they have no idea what they’re getting involved with or what the consequences will be. Alexander Nikolaevith Hell is an Iron Qwaser, one of many opposing factions of super-warriors.

Struggling yet brilliant, 19-year-old Minato Sahashi has failed his college entrance exams for the second time, resulting in him being regarded as worthless by those around him. However, the course of his seemingly bleak future is altered dramatically when a beautiful, supernatural woman falls from the sky and into his life. That woman, Musubi, is a "Sekirei," an extraterrestrial with extraordinary abilities. Recognizing the potential of the Ashikabi gene within Minato, Musubi kisses him, initiating a bond between the two of them. This drags him into the high-stakes world of the Sekirei, where he and his new partner must compete against others in a battle for survival called the "Sekirei Plan." However, unbeknownst to the contestants, there is far more at risk that what the competition initially entailed. Manga series by Sakurako Gokurakuin.

Kaoru is a college boy with everything going for him. He lives in a mansion with his beautiful fiancé, Aoi, all his roommates are babes, and they all have the hots for him. There’s just one hitch: due to family complications, Kaoru and his beloved have to keep their engagement a secret. As he gets tangled in countless steamy situations, can Kaoru overcome temptation and stay true to the lovely Aoi?

Upon winning a fighting tournament and being crowned the world’s strongest warrior, Peter Grill discovers a downside to his newfound fame. Women of all species, from ogres to elves, are scrambling over each other for his seed to ensure they have the strongest babies possible. Poor Peter just wants to settle down with his lovey dovey fiancée, but he’ll have to outmatch, outwit, and outrun a harem of very determined monster girls to do so!

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.

Narcotics Enforcement Agent Riko Ikazuchi is undercover with her junior colleague Noma in an apartment that serves as the hideout for a criminal organization. Despite Riko and Noma posing as a newlywed couple, the criminals begin to suspect them after not hearing any marital intimacy during the night. To convince them that they are a loving couple, Noma starts touching Riko's body...

The story takes place in Japan in the early 21st century, in an alternate reality where the Tokugawa Shogunate has remained in power. In this reality, student councils are tasked with oppressing schools. Yagyuu Muneakira is a high school student who rebels against his student council with the help of girls who've had the names of famous samurai heroes passed on to them.

Ranma Saotome, a teenage martial artist, and his father Genma travel to the 'cursed training ground' of Jusenkyo in China. There, despite the warnings of the Chinese guard, they fall into the cursed springs. From now on, whenever Ranma is doused in cold water, he turns into a girl and a cute, well-built redhead at that. Hot water changes him back into a man again, but only until the next time. To make matters worse, his father engages him to Akane Tendo, a girl who hates boys.

Hida Kizuna possesses the HHG (Heart Hybrid Gear) ability, but it is not strong enough to make him particularly important. His older sister calls him to transfer to a strategic defense school, where many of the students (many of which are large-breasted girls) use their HHG abilities to fight invaders from another world while wearing extremely skimpy pilot outfits. Kizuna's fighting ability doesn't measure up, but his sister has another plan—apparently having erotic experiences with Kizuna will allow the girls to replenish their energy or power-up. It looks like his new school life is going to be full of embarrassment.