Himeiden

The story follows Kuu Sorakara, an unfeeling boy who always puts on a mask of emotion to hide the fact that he can never feel any emotion. One day, a scream was heard all around the world, killing a third of the human population. Six months later, Kuu confesses his unfeeling disposition to a doctor during a check-up, thinking nothing of it. The doctor, however, has ties to an organization known as the Earth Eradication Army, a force fighting to destroy the Earth itself, as it is trying to terminate the human race (the scream being caused by it). The Army deems the boy to be a perfect candidate to become a hero, logically determining that since Kuu is unfeeling, he can never have any weaknesses born of human compassion, and therefore can become the best fighter against the Earth. And so, they send Kenka Kendou to kill Kuu's parents and siblings, and also dispose of every one of his acquaintances, no matter how insignificant their interaction may have been, in order to "sever all of his attachments to his old life." Thus, Kuu joins the Earth Eradication Army, having nothing better to do. (Source: Nisioisin Wiki)

Six months ago, a scream was heard all around the world, killing a third of the human population. The story follows Sorakara Kuu—the boy who is not moved by anything, whether happy or sad; whether it's comedy or tragedy.

What if Monogatari's Ararararagi, Zaregoto's Ii and Jun "Humanity's Strongest" Aikawa, and Okitegami Kyouko no Bibouroku's titular forgetful detective all attended school together? In 2002, NisiOisiN won a Mephisto Prize prize for his debut novel Zaregoto, Book 1: The Kubikiri Cycle. Part of the 15th anniversary celebration will be 4-panel crossover gag manga Seishun Kijin-den! 240 Gakuen (240 is a pronunciation pun - 240 can be read as "Nishio," so "Youth Oddball Story! Nisio Academy"). (Source: Crunchyroll)

A series of crossover stories between characters from Monogatari and characters from Nisio's other works. Originally, 4 crossover short stories were released during the theatrical screenings of each Kizumonogatari movie. The stories were bundled up into Mazemonogatari, and included 3 unreleased stories. Includes 15 stories: Kyouko Balance Jun Build Nomi Rule Mayumi Red Eye Kuroneko Bed Risuka Blood Hitei Clear Iori Fugue Shiogi Ranger Akari Triple Rizumu Rock 'N' Mikoko Community Kuu Invisible Rai Roulette Magakoro Finisher