Complex sentence: Lucario thinks of Sir Aaron as both his master and close friend, although after Aaron traps him in a magic staff at the film's outset, Lucario begins questioning any Pokémon-human relationship.
Split into simpler sentences: Lucario thinks of Sir Aaron as both his master and close friend. After Aaron traps him in a magic staff at the film's outset, Lucario begins questioning any Pokémon-human relationship.