Prolific manga writer Kazuo Koike passed away on April 17, 2019, at the age of 82, due to complications from pneumonia. Koike was a writer best-known for his work on Lone Wolf and Cub, though his career spanned decades and included dozens of other series.

Koike began his career studying under Takao Saito, the creator of Golgo 13; Koike would later act as a writer for Golgo 13. Alongside artist Goseki Kojima, Koike created Lone Wolf and Cub, which debuted in 1970. The story followed Ogami Itto, an executioner who later becomes an assassin after losing his power under the shogun due to false accusations from the Yagyu Clan. He takes his three-year-old son with him while seeking his revenge, and the two become known as the titular “Lone Wolf and Cub.” The story proved to be hugely popular around the world, later being adapted into a series of films as well as a television series. Many American comic creators have credited Lone Wolf and Cub as an inspiration, such as Frank Miller, who would later go on to produce cover artwork for Dark Horse’s English-language releases. Koike himself contributed scripts to many of the live-action adaptations of his work, and would also produce the 1993 film, Lone Wolf and Cub: Final Conflict.

Koike’s later work included Crying Freeman, another assassin-focused story in which the main character, a man hypnotized by the Chinese mafia to act as a hitman, weeps after every killing due to subconscious regret. This was later adapted as an anime OVA and three live-action films.

Though many of Koike’s work dealt with violent themes, he also dabbled in more wholesome activities, writing stories focused on golf and mahjong (as Koike was both an avid golfer in his spare time as well as a former professional mahjong player).

He would also work with Marvel several times over the years, penning Hulk: The Manga in the 1970s and later contributing stories to X-Men Unlimited.

Later in his career, Koike founded the Gekiga Sonjuku, a college course that aimed to teach people how to become a successful manga artist. Graduates of his course included Rumiko Takahashi (creator of Ranma 1/2, InuYasha, and more), Hideyuki Kikuchi (writer of Vampire Hunter D), Tetsuo Hara (artist of Fist of the North Star), Yuji Horii (game designer and writer behind the Dragon Quest series), and many more.

In 2004, Koike was inducted into the Will Eisner Hall of Fame.

Koike’s passing comes just days after the death of Kazuhiko Kato/Monkey Punch, the creator of Lupin III; the two had considered each other rivals during their time writing stories for Weekly Manga Action magazine. Koike Tweeted about Kato’s death following the news, saying how much he had loved Lupin III and hoped that Kato’s soul was at rest.