Issei Hyoudou (兵ひょう藤どう 一誠いっせい, Hyōdō Issei) is the main male protagonist of High School DxD. He is a third-year high school student at Kuoh Academy in Class 3-B and a member of the school's "Perverted Trio", a trio of the most perverted men in the entire student body.

Issei is the Pawn of Rias Gremory's Peerage and a member of the Occult Research Club. After the Evil Dragon War, he was promoted to the rank of a High-Class Devil, becoming the King of his own independent peerage, and is one step closer to fulfilling his dream of having a harem and becoming a "Harem King".

Due to his possession of the Longinus; the Boosted Gear, which hosts the Welsh Dragon, Ddraig, Issei is the direct rival of Vali Lucifer, who is the host of the Vanishing Dragon; Albion, who is Ddraig's archrival.