Shimizu Kenta's high school life changed when he was seduced by Aoi Riku as a joke who then proceeded to bully him mercilessly. However, a messenger from hell named Beatrice came and gave him a choker so that he can dominate sinful women as an executor.

From MangaHelpers:
In high school, Maki Eiji was a delinquent, often skipping class and getting into fights. One girl, Chino Kotoha, was kind to him, until she was targeted by delinquents due to their apparent relationship. Suffering their attack seemed to have permanently changed her for the worse.
Years later, when Eiji sees her again, he is overcome with guilt and regret. To his surprise, a mysterious scantily-clad woman suddenly appears, claiming she can send him back in time to make everything right! He takes her up on the offer, but things are not as simple as they may have seemed back then. It turns out that Kotoha had her own painful secrets in those days, and Eiji may not be the only one traveling in time to change the past.

Touya, a boy whose face was too scary, was enthusiastic about Inami-san, the most popular girl in the school, But she had a dark side....!!

Yoseob, normally very quiet and composed, is in the police station convicted of stabbing 8 civilians with a knife. Everyone's wondering whether he actually committed the crime. Does he, a mere high-schooler, really have any reason to have done such a horrifying act? Does his obsessive love for his older brother, Jaeha, have something to do with it?

Shiba, a college student with a communicative disorder, has been reading rumors circulating on Internet forums about women 'clones', which look like a human, but are not actually a human! Instead they are perfectly obedient to their owner's orders and fulfill every desire! This should have been hastily dismissed as an urban legend but then an incident started when Shiba was hospitalized after an accident...

Ajafuji Sara transferred to the private Fujigamine Academy. She suffers from extreme blushing and dreamed of making friends at the academy and having an "ordinary student life". However, having met at the scene, Kazari Iris set her eyes on her. Will her dream crumble away?

This story starts after events in Episode G.

"In his house at R'lyeh, dead Cthulhu waits dreaming..."
The Greater Cthulhu Mythos based on information from works in the Mythos. By default, all information is to be assumed to derive from the Lovecraft Myth Cycle unless otherwise marked.

Despite her clumsiness, teenage school girl Chihiro is popular at her school, especially with the boys. She joined the wrestling club a few months back and has been practicing without much apparent success. However, she wins her first competition surprising everyone including herself and her fan boys become more passionate about her. Will Chihiro be able to become an amazing wrestler?

Honori joined the suspicious-fun club, the "Substitute Club", which substitutes for people and does their work for them. The members of this handy-man type club are very free-willed and loyal to their desires.

Sakura, a 1st-year student at a music high school, loves playing piano. She also quietly loves her friend, Nanoha. Nanoha has adored listening to Sakura play the piano ever since they were children. As the yearly music competition for upperclassmen comes around, Sakura will have to deal with her passion for both the piano and Nanoha.

Set in 2025, a roboticist named Fudou Yuuki joins a project involving a large mural depicting humanity's true past as well as the ancient but advanced technology found in Antarctica.

The prequel to Black Jack, Osamu Tezuka's classic series about a brilliant maverick doctor who practices without a license. This story follows Black Jack when he was still a young, unorthodox medical student in 1968.

Yukishiro Nanako is a cute, cheerful high school girl with one peculiar trait – instead of verbal communication, she writes senryu (a type of haiku) poems to relay her thoughts. Together with ex-delinquent Busujima Eiji, they are budding freshmen of the school’s Literature Club.

Even though Nanako doesn’t talk, with the power of senryu, the adorable pair has no problem enjoying their fun school-life through the tune of 5-7-5 syllables.

The story follows Tachibana Misaki, a 15-year-old girl who's bullied at school. In her quest to become stronger, she decides to enter the delinquent path, aiming for a shinny tomorrow.

From: Easy Going Scans
The story begins with the eradication of Qing-cheng martial art faction by a group of martial art fanatics from Wudang, whose master and disciples only has one belief – to become the strongest in the world. In order to maintain their supremacy, they take over all the other martial arts group and kill those refuse to yield themselves to them.
Yan Heng, a young swordman in Qing-cheng, was saved by ‘Wudang Hunter' Jing Lie, who also lost his fellows because of Wudang. Being the only remnant of their groups, the two allied and start their journey of revenge.

Prequel to "Rakujitsu no Pathos" where we see Yuuki working as a school teacher and get to understand how things came to be...

Tooru and his sister Yume end up in hospital after a traffic accident leaving their father brain-dead when suddenly Itou Yuuzen appears out of nowhere and takes them under his “religious cult's” protection. Is this the beginning of a new life for the brother and sister or something is hidden behind the facade of this religious cult?

"So many demon spirits, I want to collect them." Long Ao Tian. Yuan Ding, goes on a journey of collecting demon spirits.

In a tranquil rural landscape, isolated and high in the mountains sits Hisatate Town. Amagase Ryou, recently moved there from the city with his family. On his first day he witnesses the strange traditions of this place and cannot believe it, as anyone who breaks the rules is punished without mercy... The residents are viciously beaten for trivial reasons. What does the future hold for the newcomers when one of them break the rules?