Complex sentence: The Rebel Alliance was featured in the original trilogy of films in which they are the main protagonist,',',', whereas its origins were referred to in' and the TV series "Star Wars Rebels".
Split into simpler sentences: The Rebel Alliance was featured in the original trilogy of films in which they are the main protagonist,',','. The faction's origins were alluded to in' and their early activities are featured the TV series "Star Wars Rebels".