Who owned the living castle in Miyasaki's film 'X's Living Castle' (Who is X)?

Explanation

Hayao Miyasaki is a master within the art of Japanese manga animation. His films feature Miyasaki's own dream universe, including everything from flying castles to red oceans. His CV includes films such as 'My Neighbor Totoro', 'Kiki's Delivery Service' and 'Howl's Moving Castle' where Sofi visits Howl's flying castle. He had his international breakthrough with the film 'Spirited Away' which received an Oscar for best animated film in 2001.