Issei Hyoudou (兵ひょう藤どう 一いっ誠せい, 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 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.