Seraph of the End 1: Guren Ichinose: Catastrophe at Sixteen

Seraph of the End 1: Guren Ichinose: Catastrophe at Sixteen is the first book of the Seraph of the End: Guren Ichinose: Catastrophe at Sixteen light novel series, which includes Guren's past with Mahiru and his encounter with many characters of the manga sequel, Seraph of the End: Vampire Reign.

It makes up the first half of the first English omnibus.

Prologue - Memories of Spring
In 2002, Mahiru asks Guren if they can get married in the future when they're older. Guren answers no, explaining that their stations are too different; as she's from the highest clan, while he's from a minor clan. People suddenly come by searching for Mahiru, and they find her with Guren. Out of rage, the group brutally beats him before dragging a sobbing Mahiru away. After that, Guren begins to yearn for power so he can be with her. A decade goes by.

Chapter 1 - Welcome to High School, Jerk
The date is April 2012.

On their way to school, a now fifteen-year-old Guren warns his two retainers, Shigure and Sayuri, about the members/students of First Shibuya High School, as they all belong to the Order of the Imperial Demons. The trio agree to stay on guard no matter what before showing up. Upon their arrival, a student throws cola can at Guren, which mimics the entire crowd to burst into laughter. Guren apologizes to Sayuri and Shigure, but he begs them to endure it. The pair reluctantly obeys.

Guren spots Shinya, who sends a Hiragi spell at him. He takes the attack on purpose and falls back unconscious. Once he awakes, he orders Shigure to retrieve him a new pair of clothes and enters school, starting the school year.

Chapter 2 - King of the Classroom
Guren is in Class 1-9 while Sayuri is in Class 1-1 and Shigure is in 1-2. Shinya Hiragi is in Guren’s class. He arrives late and then says he wants to help Guren bring down the Hiragi Clan.

Chapter 3 - Top of the Class
Mito Jujo jabs at Guren while the principle gives the opening speech. Shigure and Sayuri move into Guren’s apartment against his wishes, and he encounters Makoto Kijima for the first time.

Chapter 4 - Reunited
The students spar against each other, and Shinya hits Guren so hard that he breaks several ribs, coughs up blood, and loses consciousness. Mahiru visits him in the nurse’s office, but he treats her coldly.

Chapter 5 - Deadly Wars and Supermarkets
Guren’s submissiveness to Seishiro Hiragi makes him lose respect from everyone in the class, including Shinya and Mito. Guren encounters Makoto Kijima for the second time, but a young boy named Mikaela addresses the man as "Mr. Saito." After Saito reveals that the Hiragi Clan is involved with forbidden magic and that there will be an attack in ten days, Guren sends a message to his father about it.

Chapter 6 - The Qualification Exams
The students fight students of other classes one-on-one in a tournament-style battle for their qualifying exams. Shigure fights Mito. Guren fights as poorly as possible and wins by "accidentally" hitting his opponent with a wild swing that knocks him out. Seishiro beats Sayuri severely and tries to strip her until Mahiru intervenes.

Chapter 7 - From Mahiru, with Love
Sayuri is hospitalized with Shigure looking over her. Guren forfeits his match against Seishiro, which leads the whole school to mock him. The Brotherhood of a Thousand Nights attacks and kills many students and teachers. Guren and Shinya fight Saito and learn that Mahiru betrayed the Hiragi Clan. Guren and Mahiru fight, and she cuts his sword, Kujakumaru, in half.

Epilogue - The Last Spring before the End
After the Order of the Imperial Demons announces it put down the "terrorist group" that attacked them before, the school reopens. Shinya helps Guren get drenched in cola again when Shigure nearly stops the attack. Mito and Goshi become friendly with Guren, Sayuri, and Shigure.

Characters
List of characters in order of appearance: