Bungo Stray Dogs: BEAST (Light Novel)

What if Ryunosuke Akutagawa, the Port Mafia’s “Black-Fanged Hellhound,” had joined the Armed Detective Agency and Atsushi Nakajima, the boy who possesses the ability “Beast Beneath the Moonlight,” had joined Port Mafia? Ryunosuke, who lost his sister and is driven by rage and the desire for revenge, and Atsushi, the “White Reaper of Port Mafia” who continues to slaughter all who oppose him. As dark and light face off, what does fate have in store for these two?
Notice: This book is written in Japanese.