High School DxD
Kuoh Academy (駒王学園, Kuō Gakuen, alt. Kuou Academy) is a former all-girls school that has recently turned co-ed, but it has a secret. Unknown to normal humans, angels (天使, Tenshi), fallen angels (堕天使, Datenshi) and devils (悪魔, Akuma) comprise part of the student population. One of these students, Issei Hyodo, is a lecherous second-year human student who lives a peaceful life. After an ordinary school day, Issei is suddenly asked out on a date by a girl named Yuma Amano. After their date, Yuma brings Issei to a local park and makes a startling request. She reveals herself as Raynare, a fallen angel, and she tries to kill him. Using her summoning card, Rias Gremory, a buxom third-year student at Kuoh Academy, revives him. Issei wakes up the next morning, thinking that the events that occurred were all just a dream. Immediately after being attacked by another fallen angel and waking up, he notices Rias naked in his room. Rias reveals to Issei her true identity as a devil and says that as a result of his death at the hands of Yuma, she has reincarnated him as a devil, becoming his new master in the process.
=== Story arcs ===
Ishibumi has grouped the light novels into story arcs. The first arc, titled The Red Dragon Emperor's Awakening (赤龍帝覚醒, Sekiryūtei Kakusei), ran through the first two volumes. Birth of the Breast Dragon Emperor (乳龍帝誕生, Chichiryūtei Tanjō) is the second story arc and follows volumes three through six. The Heroic Oppai Dragon (英雄（ヒーロー）おっぱいドラゴン, Hīrō Oppai Doragon) follows volumes seven through twelve. The fourth arc, The Legend of Oppai Dragon and his Lively Companions (おっぱいドラゴンと愉快な仲間たちの伝説, Oppai Doragon to Yukaina Nakamatachi no Densetsu), follows volumes fourteen through twenty-one.  The fifth arc, Red Dragon Emperor of the Blazing Truth × White Dragon Emperor of the Morning Star: The True Dragon(s) of the Kuoh Academy ((明けの明星の燃え立っているTruthx白ドラゴン皇帝の赤いドラゴン皇帝：Kuohアカデミーの真実のドラゴン（s)), starts at volume twenty-two and is the final arc of the series.
The light novels also feature a series of side stories set in between the main storyline, and are often compiled into volumes. So far, three short story collections (Volume 8, Volume 13 and Volume 15) have been published.
sadist