A champion of a cause is someone who actively works to promote and support a particular issue or belief. An ADVOCATE is someone who speaks up in support of a cause, while a PALADIN is a heroic champion of a cause. An EXPONENT is someone who promotes or advocates for a cause, and a CRUSADER is someone who is passionate about a cause and works to bring about change. All of these terms refer to someone who is dedicated to a cause and works to bring about positive change.