High School D×D is a popular Japanese anime series that follows the story of Issei Hyoudou, a high school student who gets entangled in a world of angels, demons, and other supernatural beings. The series is known for its blend of action, comedy, and ecchi elements, as Issei navigates his new life after being reincarnated as a demon. It has garnered a dedicated fanbase for its engaging plot and dynamic character development.