In 1972, Maruyama left Mushi Productions, which was facing a financial crisis, to found Madhouse, along with his colleagues including
Osamu Dezaki,
Rintaro, and
Yoshiaki Kawajiri, and in 1980, he became the president. Since then, he has focused on planning, producing and production design for numerous Madhouse TV series, OVAs and theatrical film. As the main producer and studio head of Madhouse, Maruyama was personally responsible for green-lighting new projects. As a result, projects were often directly pitched to him by outside interests or brought to him by creators within the company. He also had a significant amount of influence in determining the staff of these new projects, particularly in the assignment of directorial duties. In addition, he was frequently involved in the planning phase of major studio productions at Madhouse. Maruyama has also planned and produced some of the best-known and rising films of famous directors, such as all of Satoshi Kon's films (
Perfect Blue,
Millennium Actress,
Tokyo Godfathers,
Paprika), Mamoru Hosoda's
The Girl Who Leapt Through Time and
Summer Wars, and Sunao Katabuchi's
Mai Mai Miracle. After the release of
Paprika, Maruyama had been preparing for Satoshi Kon's next film,
Dreaming Machine, but the film's production has been suspended when Kon died suddenly in August 2010. In 2010, Maruyama served as the executive producer for an anime project based on the TV show
Supernatural, entitled
Supernatural The Animation, and is the world's first animated project from a Japanese anime studio based on an overseas drama series. From 2010 to 2011,
Iron Man,
Wolverine, and
Blade, three works from the
Marvel Anime Project, of which Maruyama is one of the planners, were broadcast on
Animax in Japan. In June 2011, Maruyama left Madhouse and established a new animation production company, MAPPA (an acronym for Maruyama Animation Produce Project Association), at the age of 70. MAPPA had a production room for Sunao Katabuchi's
In This Corner of the World since the very beginning in 2016. At the age of 75, Maruyama wanted to execute at least two more big projects, so he established the studio to prepare for the execution of his projects even if he was gone. ==Works==