Seraph of the End 4: Guren Ichinose: Catastrophe at Sixteen

Seraph of the End: Guren Ichinose: Catastrophe at Sixteen (Volume 4) is the fourth volume 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 is expected to be published as the second half of the second English omnibus.

Prologue
Guren Ichinose contemplates what he should do while facing imminent failure: 1) give up, 2) keep trying anyway, or 3) fight to fulfill your ambitions and risk losing everything else. Guren chooses option three.  He is filled with desire and despair.  In a small alley, he risks his humanity and grasps the demon weapon Noya.  He senses the Apocalypse begin.

Chapter 1
Guren hears a voice calling his name and awakens in a completely white space in his heart. The demon Noya tempts him with power and approaches him. He chats about Mahiru and says that Guren will turn into a demon regardless of whether he accepts that power or not. Guren touches Noya and willingly gives up his humanity, leading Noya to mock him for making the wrong choice. He says it is unacceptable for a human to give up on his humanity while he is still human. Everything goes black, and power overwhelms him.

Guren wakes up with the sword in his and a motorcycle next to him. He hears war going on all around him but no longer feels any pity or empathy. His desires encourage him only to kill, and he mutters about needing a sheath to suppress the demon's will before getting onto the motorcycle.

Chapter 2
War breaks out at school, and Shibuya looks like a war zone.

Goshi reflects on his inferiority complex toward his younger brother while holed up in the girls' restroom.

Guren arrives, killing many Hyakuya Sect members, but Noya is mostly in control. Noya causes Guren to kiss Mito and grows horns, fangs, and claws.

It is revealed that Mahiru cast an illusion over the entire school.

Mito and Goshi narrowly escape while Shinya and some Mikado no Oni soldiers seal Guren within the school. Shinya contacts Sakae, who is willing to give his research over to the Mikado no Oni and accept any punishment so long as they save Guren.

Epilogue
Mito, Shinya, and Goshi play video games at Guren's place until Mahiru appears. Guren attacks her, and they fall from the twenty-fifth floor. Mahiru uses her sword to stop her fall, and Guren is badly injured but recovers.

Characters
List of characters in order of appearance: