Musashi does not appear as a character in the film "Pokémon Heroes - Latias & Latios". The film focuses on central characters like Ash, Misty, Brock, Latias, Latios, Bianca, Lorenzo, Annie, and Oakley. Team Rocket (Jessie, James, and Meowth) are present but have a limited role, mainly witnessing events or pursuing the villains Annie and Oakley. The provided materials contain no background story, character development, or specific actions for Musashi related to this film.