Issei Hyodo is a lecherous second-year high school student attending Kuoh Academy (駒王学園Kuō Gakuen),
a former all-girls school that has recently turned co-ed. He lives a
peaceful life until he is called for a date by a girl named Yuma Amano.
At the conclusion of the date, Issei is brought to a local park, where
Yuma asks him if he wants to know what her wish is. Under the impression
of receiving a kiss from the girl, Issei is shocked when Yuma whispers
the words "Can you die for me?" and transforms into a Fallen Angel.
Issei is brutally attacked and killed by Yuma. Issei wakes up the next
morning, believing the events that occurred were all just a dream.
Immediately afterwards, he notices Rias Gremory,
a buxom third-year student at Kuoh Academy, naked in his room. Rias
reveals her identity as a Devil to Issei and claims that she has
reincarnated him as a Devil who will serve as an underling to her and
the Gremory Devil Family.