Bungo Stray Dogs 1 by Kafka Asagiri
Having been kicked out of the orphanage, a despairing young man by the name of Atsushi Nakajima rescues a strange man from a suicide attempt--Osamu Dazai. Turns out that Dazai is part of an armed-detective agency staffed by individuals whose supernatural powers take on a literary bent! When Nakajima is engaged by Dazai and his associate Kunikida to hunt down a man-eating tiger terrorizing the region, little does [he] suspect that the encounter will transform his life forever!