Kotaro Isaka is a Japanese writer of mystery fiction, best known for the Hitman novel and manga series. The first of those novels, 3 Assassins, appeared in Japan in 2004 and was adapted as the Japanese film Grasshopper in 2015, while the second, Maria Beetle, from 2010, became the American film Bullet Train in 2022. Isaka's other work includes Maoh: Juvenile Remix, published between 2007 and 2009.
