High School DxD

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.*

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.

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)

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.

Short stories bundled with the first press release of the Blu-Ray/DVD volumes of the High School DxD BorN anime. The Occult Research Club faces off against invaders known as Underworld Lifeforms led by Loki that have travelled from the future. However, the future also brings a surprise visit by Issei's children. (Source: highschooldxd.wikia)

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

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

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)

Junior High School DxD is a spin-off series that takes place after the events of Volume 10 of the original High School DxD Light Novel series. Junior High School DxD follows Zekka Miyamoto, a descendant of Miyamoto Musashi, blessed (or cursed) with her sword 'Tensei' that steals power from enemies' breasts, transferring them to her own. After learning that 'Tensei' is a weapon called a sacred treasure, Zekka knocked on Kuoh Academy Junior High School's door to uncover this mystery and make friends! And then she met... the red-haired demon Rias Gremory. A new DxD story of youth at Kuoh Academy, surrounded by eccentric seniors and classmates, and with highly promising sword skills!"