I’m going to make this school my harem! When a cute girl asks Issei out, he believes his twisted fantasies are finally coming true. Too bad the girl sprouts a pair of black wings and stabs him with a spear on their first date! Saved by his school’s number one beauty, Rias Gremory, Issei is transformed into a demon and made her servant. Issei hopes to rise through the ranks of demonkind to grow powerful enough to create his harem, but in a city with fallen angels and insane priests, he’ll be lucky if he can live long enough to do it! (Source: Yen Press)

Shin High School D×D is a light novel series set in the High School DxD universe. Continuing from where Volume 25 of the previous light novel series left off, high school student-turned-devil Issei Hyoudou is still pursuing his dream to be a harem king. (Source: TV Tropes)

When unpopular high schooler Issei Hyoudou has a less than romantic encounter with his first-ever girlfriend, the consequences are fatal! As he lies dying, who should come to his rescue but the prettiest girl in school, Rias Gremory! And the shocking truth she shares leaves Issei reeling... "You've been reborn a devil. Now you work for me!" Issei's uproarious life as a devil's minion begins here! (Source: Yen Press) *Note: Includes two extra chapters.*

Manga adaptation of the short stories found in the eight volume of the light novel.

Caught with a severe fever, Tobio Ikuse, a second-year high school student, was forced to miss his school trip on a luxury liner with his schoolmates. Four days later, Tobio hears the news about the disappearance of the teachers and second-year students from his school, and it devastates him. A few months after the incident, Tobio, having slowly recovered from the sudden loss of his friends, accidentally encounters one of them again. Chasing after his missing friend Sasaki, Tobio finally manages to catch upto him, but is shocked to see Sasaki alongside a Lizard Monster who attacks him together with the monster. Cornered by the monster, Tobio is rescued by another survivor of the missing luxury liner, Natsume Minagawa, who then hands him an egg before parting ways. Later that night, Tobio finds himself under attack, again, this time by two people with monsters. Amidst all the ensuing chaos, out of Tobio's shadow, came out a Puppy that rescues him. After fending off the two monsters, Natsume once again approaches Tobio before finally deciding to take him to their hideout.

High School DxD DX is a compilation that consists of already published short stories on various issues of Dragon Magazine and as well as newly written ones.

Spin-off of High-School DxD that deals with the lives of two cute girls in the group, this takes place after Chapter 10 of the main manga series

A new student steps up to the gates of Kuoh Academy junior division. Zekka, a descendant of Miyamoto Musashi, wields the sword-shaped Sacred Gear "Tensei." Her goal? To make friends at Komaou Academy!? A new "DxD" series begins, guided by unique friendships and by Rias and the other high school students! (Source: Kadokawa, translated)

Caught with a severe fever, Tobio Ikuse, a second-year high school student, was forced to miss his school trip on a luxury liner with his schoolmates. Four days later, Tobio hears the news about the disappearance of the teachers and second-year students from his school, and it devastates him. A few months after the incident, Tobio, having slowly recovered from the sudden loss of his friends, accidentally encounters one of them again. Chasing after his missing friend Sasaki, Tobio finally manages to catch upto him, but is shocked to see Sasaki alongside a Lizard Monster who attacks him together with the monster. Cornered by the monster, Tobio is rescued by another survivor of the missing luxury liner, Natsume Minagawa, who then hands him an egg before parting ways. Later that night, Tobio finds himself under attack, again, this time by two people with monsters. Amidst all the ensuing chaos, out of Tobio's shadow, came out a Puppy that rescues him. After fending off the two monsters, Natsume once again approaches Tobio before finally deciding to take him to their hideout.

Kanzaki Mitsuya is a high school student who enjoys video games. On one particular day of his boring life, a strange email arrives on his mobile phone. It is an invitation to the game known as [Innovate]. Out of boredom, Mitusya decides to register and participate in the game… Source: NU

Caught with a severe fever before his school trip, Tobio Ikuse, a second-year high school student was forced to miss out his school trip with his schoolmates on a luxury liner. Four days later, the news about the disappearance of the teachers and second-year students reaches Tobio's ears. Few months after the incident, Tobio having slowly recovered from the shock accidentally encounters one of his classmates again. (Source: High School DxD Wikia, edited)