Zerozaki Hitoshiki no Ningen Kankei: Niounomiya Izumu to no Kankei

"It might not be bad to commence the Zerozaki." The strongest "Sound User" appears. The Zerozaki Clan is a family of demonic killers, ranked third among the Killing Names. Zerozaki Magashiki, known as "Girly Tastes (Bolt Keep)", senses a danger creeping up on the clan and finally appears on the stage. What will happen to the unity of the clan? The battle of the "sound user", Zerozaki Magashiki, begins now! The forefront of the new youth entertainment is here! (Source: Kodansha, translated)

The Zerozaki Clan is a family of demonic killers, ranked third among the Killing Names. Having just become siblings, Zerozaki Hitoshiki and Mutou Iori attack Aikawa Jun—Humanity's Strongest Contractor—with the best intentions. But, as a result, get caught up in her work! They're headed towards the domain of the second-ranked Killing Names, the Yamaguchi Folks, on the island of Taiyakujima. Therein lies the Lifelong Undefeated Crystal Kaiser, Rikka Kajumaru. (Source: Kodansha, translated)