Complex sentence: A subgenre of the action film, martial arts films contain numerous martial arts fights between characters, usually as the films' primary appeal and entertainment value, and often as a method of storytelling and character expression and development.
Split into simpler sentences: A subgenre of the action film, martial arts films contain numerous martial arts fights between characters. They are usually the films' primary appeal and entertainment value, and often are a method of storytelling and character expression and development.