Based on the erotic game by Ume Soft. 
 
Wakasa Souji is someone who is too obsessed with Ominato Natsuko, a cute girl who works in a Supermarket. Due to lacking the expertise to communicate and talk with Natsuko, Souji only paid close attention to Natsuko. Natsuko has recently been dating Shibata the handsome but Playboy man, and he plans to take Natsuko in just 1 week to kiss and sex. That's why Souji wants to save Natsuko from that goddamned man in his own way. 
 
(Source: Nekopoi and Has Been Translated and Edited)

Based on the erotic game by Waffle. 
 
The bastard son of a rich aristocrat is hellbent on seeking revenge ever since his father abandoned him and his mother. He decides to teach his father a lesson by destroying what he treasures the most, his two daughters. He infiltrates their prestigious school with a magical time-freezing device he received from a witch—and proceeds to repeatedly rape his half-sisters, leaving them confused, helpless and begging for mercy.

Based on the erotic game by Waffle. 
 
Tezuka Ryou recently lost everything: his sister whom he loved intimately, his father due to a fire at his house and now in depression he seeks revenge on the people who caused him all this trouble. He kidnaps the 3 girls that bullied his sister into committing suicide. He then starts to torture them by raping them and live streaming it all so when they confess, the whole world can see it. 
 
(Source: Visual Novel Database)

A cross over between the two hentai RIN&times;SEN and RAN&rarr;SEM.

Based on the erotic game by Tinker Bell. 
 
An elite Academy that specializes in the highest person's position and is free to do anything to a lowly person. In essence, many students feel arrogant because of the position above. 
 
(Source: Translated and Edited from Nekopoi)

Based on the erotic game by Guilty eX. 
 
Tanabe Yoshiyuki disappears because of the frequent oppression done to her at school. Nagisa, Yoshiyuki's cousin, decides to dress as a man in order to find out what happened to her and take revenge on those responsible for the persecution. 
 
(Source: Translated and Edited from Nekopoi)

The staff members of a certain hentai producing company get personally involved in their work. Perhaps a little too involved as some some male staffers begin to cross the line between fiction and reality.

After the disappearance of her sister and finding out she had joined a suspicious enlightenment group seminar, Riko enlisted herself into the course to find her but the only way to reach the same course as her was to rank up and the only way to do so was to help others release... that being through sex.

Based on the erotic game by Guilty. 
 
Raika's brother died suddenly. She changed to her brother's school (all-boy school), so she could to find why he committed suicide. Someone interferes with her and discovers her identity leading closer to the truth behind her brother's death.

Based on the erotic game "Toriko Hime - Hakudaku Mamire no Reij&#333;" by Guilty. 
Minase Shizuru is the daughter of a rich politician. This being so, she attends a prestigious academy together with friends of a similar status. However, her life is turned upside down when she gets kidnapped by members of Tsuruma Consulting, including her own classmate, the young master Tsuruma who is the son of the company's owner. They force Minase and her friends from the academy to be sex slaves for test subjects in their research facility. Together and with determination, Minase and her friends try to devise a way out of this small slice of hell. 
(Sources: ANN, AniDB)

Based on the erotic game by Speed. 
 
Four years have passed since the initial outbreak of the Unknown virus epidemic, and the terrifying plague which depopulated the Tohoku region of Japan has been reduced to a mere memory, thanks to drastic quarantine measures coupled with an effective vaccine. 
 
But the Unknown virus is not dead yet and soon, very soon, an unescapable doom will fall upon Wataru Ayase and his family and friends, trapping them inside the "Hell on Earth" madhouse which originally was their home city, Tokyo... 
 
(Source: Visual Novel Database)

Kurata Ibuki and Miyauchi Akira are two very attractive virgin girls. Happily thinking they just won a prize at a summer resort for week, turns out to be a trick from some upper-class students at their school. The mastermind behind this whole "abduction" now have a whole week to train them to sex slaves. Will he successfully turn them to the dark side or will they struggle to the end and prevail?

It was just supposed to be a summer training.... Yuki is a caretaker of the baseball club. She and other members stay at a training camp on the isolated island now. But one day, a civil war breaks out. Male teachers leave the island to see what's going on. However, they never come back. Several days later, they know that their ship is wrecked. Nothing to drink.... Nothing to eat.... They gradually lose their self-control.... 
(Source: ErogeShop)

Urara starts working at a girls' school. She is now happy because she will get married in a few months. But one day, her fiance suddenly goes missing since his business didn't go well. Months later, Yuji, a debt collector, comes to her house, but she doesn't have enough money to pay. Yuji offers her to work at a boys' school his friend works. He also says if she works there for a month, she won't need to pay back money. She finally decides to accept his offer without knowing the fact that the school is full of evil teachers and students.... 
(Source: ErogeShop)

Based on the erotic game by Speed. 
 
Kansen 2 (like the first episode) takes place during the initial outbreak of the Unknown virus epidemic, but the protagonists here have a much harder lot because they are stuck in the middle of a contaminated city immediately after its destruction by a mysterious cataclysm. 
 
Stalked by hordes of infected maniacs, Hiroshi Ookura and his friends seek safety inside a mostly intact shopping mall, but madness and death are everywhere... 
 
(Source: Visual Novel Database)

Kaoru is a high school student who does not have the guts to go against his old friend Nanao. Nanao keeps giving Kaoru sexual orders which he is forced to obey. One day he decides to take revenge. And for the revenge he will use his other classmate Mayu as his trump card.

Based on the erotic game by Speed. 
 
Extracurricular club activities are the norm for Japanese schools, but an all-night movie event scheduled at school and in August still sounds strange/unusual, especially considering the tiny size of the Movie Research Club (merely six students). And indeed, the two teachers supporting this novelty have hidden motives/objectives, although also the six students themselves chose to participate in the event for personal/secret reasons...

Junko lost her husband about ten years ago and she has been bringing up Ryouichi, her son, alone since then. One day, when he is asleep, she secretly gives him a blowjob and has sex with him. Two years later, she gets remarried.... One night, he accidentally sees Junko and his new father having sex. He remembers what happened two years ago and feels an irresistible impulse to get her back.... 
(Source: Saishuu.com)

Chinetsu Karte is a tale about a young man who seduces the very beautiful nurse assigned to his room while he's in the hospital. He soon has her coming back again and again until she becomes his sex slave. In time, he makes a move on other nurses and even on one of the female doctors in the hospital until they, too, come under his spell. 
(Source: AniDB)

Miu and her family of four women are well-known in the media for being aspiring young celebrities. Her mother, Sayoko, is a famous fashion designer and has scored a job for the family to shoot a TV production; a rare opportunity for the family to be together and enjoy themselves. The girls travel to a small, isolated village in late August and the filming begins. Little do Miu and her family know however, the entire production is a scheme. This is the time for a local festival and they happened to unwillingly volunteer to be a key figure for this festival; the Shishigami. One by one, the girls are subjected to the traditions of the festival, experiencing first-hand just how serious it is. 
[Written by MAL Rewrite]

Even though Masaru is about to graduate from a technical college pretty soon he still has no job. One and only pleasure for him is to spend time at a cafe called "Hidamari". The cafe is owned by his childhood friend's Nanami and Kurumi's parents and they are working there too. One day, he learns another one of his childhood friends is coming back to his town. He says "I wanna meet her soon.". Triggered by his word, Nanami and Kurumi start to approach him in a very different way than they ever did before... 
(Source: ErogeShop edit)

Based on the erotic game by Bishop. 
 
While riding the train, some girls get into trouble.

Based on the erotic game by Bishop. 
 
Due to a school conspiracy, Tetsuya is forced to drop out of school. In order to satisfy his need for revenge, Tetsuya needs to get his hands on Haruna, the principal's daughter. However, to do that, he needs another to girl to lure Haruna out. That's where Ayano comes in... 
 
(Source: AniDB)

An earthquake causes the school campus to collapse living only 4 survivors - 2 childhood friends, Fubuki &amp; Shinichi with Takahaki and a Junior girl. Both Shinichi and Takahaki likes Fubuki, but Fubuki likes only Shinichi. Takahaki made false accusation on Shinichi having interest on the Junior, whom also likes Shinchi, in front of Fubuki to create a doubt between both childhood friends. And making use of the situation and raped the Junior and of course.... Fubuki. Leaving Shinichi in a mist of doubts.
 
(Source: Anime News Network)

Suzuki Mirano