Captain Marius (Japanese: カイドウ Kaidō) is a character of the day in the Pokémon anime.
Marius is a captain and fisherman who appears weathered from years on the sea. In Around the Whirlpool, Marius was piloting the boat which helped rescue Ash and his friends after they had been blasted off a boat by Team Rocket.
Marius is deeply interested in Pokémon. He asked Brock about all of the gang's goals and dreams, and admired all of them deeply. He traveled with Professor Elm, who holds him in rather high esteem, during his trip in the Whirl Islands. But Marius is also very modest, as he asked Professor Elm to stop bragging about all of his accomplishments.