The Red Dragon Emperor's Awakening (赤龍帝覚醒 Sekiryūtei Kakusei) is the the first story arc of High School DxD. This story arc follows the first two novels of the series, the first four volumes of the manga, and the first season of the anime.
Part 1: Welcome to the Occult Research ClubEdit
The story begins with Issei Hyoudou who was killed on his first date by his first girlfriend, moments before his death, he thinks of a girl with red hair that is the same color as his blood. He wakes up the next morning thinking that it's a dream. Surprised that none of his friends remember Yuuma Amano, his girlfriend, telling him that it's his imagination. After spending an evening in his friend's house, Issei goes to the park where he last met Yuuma, and was confronted by a man with black wings, as the man attacks Issei. Before the man can kill Issei, the crimson haired girl, Rias Gremory, comes to Issei's rescue as the man, a Fallen Angel Dohnaseek, retreats. Issei wakes up again the following morning but this time to his surprise, he finds a naked Rias sleeping besides him. Rias then introduces herself to Issei and her identity as a Devil and his master. After class at school, Issei was confronted by a different man this time, Yuuto Kiba, who came to escort Issei under Rias' command. Escorting Issei to the Occult Research Clubroom, where he meets two other girls, Akeno Himejima and Koneko Toujou, as Rias reintroduces themselves as Devils of the Gremory Clan.
Part 2: Asia Argento, the Holy PriestessEdit
Accepting his life as a Devil, Issei starts to aim to get his own Evil Pieces so that he can become the Harem King of his desire. On his way to school after failing two jobs in a row, Issei meets a nun named Asia Argento, who lost her way, as Issei guides her to the church on his town. Closing to the church, Issei gets an unpleasant feeling as he parts way with Asia. Back at the Occult Research Club. Rias then scolds Issei, warning him to never get close to the church or risk being killed by Angels and exorcist. Rias and her peerage then goes to eliminate the Stray Devil, Viser, with Rias revealing the position of each of her servants, as they eliminate Viser. On his next job after the Stray Devil hunting, Issei accidentally meets a strayed exorcist, Freed Sellzen, who killed Issei's client, before turning his attention to Issei. Issei eventually fights Freed after being disgusted by Freed's action and how he treats Asia, his partner, despite the initial surprised. Being inexperienced, Issei was nearly killed until the timely interference of his friends, who retreated before a group of Fallen Angels leaving Asia behind despite Issei's objection.