High School D×D

Issei Hyodo's awkward first date takes a dark turn when his new girlfriend transforms into a monster and attacks him. He is rescued by Rias Gremory, the attractive president of the school's Occult Research Club, leading to a series of bizarre and unexpected events.

The Occult Research Club is shown to be made up entirely of devils, including the new and struggling member Issei, who is still learning to control his demonic powers. As he attempts to adjust, he must also deal with the sudden appearances of Fallen Angels who are determined to kill him.

Issei encounters Asia Argento, a nun who has arrived to work at the local church, and a friendship begins to form between them. At the same time, he starts to grasp the broader, chess-like game involving devils and the roles he and his classmates are destined to play within it.

Issei aims to enhance his strength and spends time with Asia, though their relationship remains complicated by external circumstances. He discovers that pawns, despite their limited power, have the ability to mimic the abilities of other chess pieces.

Issei, with the support of Kiba and Koneko, attempts to rescue the severely injured Asia, resulting in a deadly duel between Issei and Raynare. At the same time, Rias and Akeno confront Raynare's fallen angels.

Asia is relocated to new living arrangements after staying in the club's room, while Issei begins a training program with Rias to improve his physical abilities. Asia also starts attending school and is placed in the same class as Issei.

Rias gives servant familiars to Issei and Asia, starting a competition between her group and the student council, who are revealed to be a rival group of devils, to see who gets to make the first selection.

Issei has a dream in which he marries Rias, which awakens a connection to his dormant dragon abilities. At the same time, Asia voices her desire to become closer to Issei.

Issei and Asia participate in a training session with the other members of their household in preparation for the Rating Game. Issei struggles to identify his unique ability, while Rias shares information about devils and the history of the Gremory family.

In *The Rating Game*, the participants are transported to a battlefield located in an alternate dimension. Issei and Koneko take on the opposing team, while Asia and Rias remain at the base. During the battle, Issei showcases his newly developed powerful technique.

Kiba battles Karlamine, one of Riser's knights, while Akeno fights Yubelluna, the queen of their forces. Issei confronts Ravel and the remaining subordinates, as Rias launches a bold surprise attack on Riser himself.

Issei awakens to discover the battle has ended and his side has lost. While Rias attends a celebration marking her engagement to Riser, Issei, aided by Grayfia and Asia, attempts to infiltrate the event, rescue Rias, and take her back with him.