Complex sentence: Anya, the more important of the two, is a vengeance demon who exacts retribition on behalf of scorned women, who lost her powers and became human, eventually falling in love with Xander and becoming a member of the Scooby Gang.
Split into simpler sentences: Anya, the more important of the two, is a vengeance demon who exacts retribution on behalf of scorned women. She lost her powers and became human, eventually falling in love with Xander and becoming a member of the Scooby Gang.