Complex sentence: Kanon later reveals that Serena is actually the surviving heir of the murdered Khans, making her a legitimate contender for the throne, she is the only hidden character that can be played in story mode.
Split into simpler sentences: Kanon later reveals that Serena is actually the surviving heir of the murdered Khans, making her a legitimate contender for the throne. She is the only hidden character that can be played in story mode.