While Lightning is the only playable character in Lightning Returns: Final Fantasy XIII, the entire cast of characters from the Final Fantasy XIII trilogy will return for the finale. Concept art confirms Serah, Mog, Caius Ballad, Yeul, and Noel from Final Fantasy X-2 will be in the game along with all of the playable characters from Final Fantasy XIII.
Noel is… different in Lightning Returns. Instead of his determined self, Noel is sullen and blames himself for the destruction of the world. Hidden away from society he is the "Shadow Hunter" and just as the Oracle Drives predicted Lightning shows up before Noel.
The two characters will fight in Lightning Returns: Final Fantasy XIII. Fueled with anger, Noel uses unpredictable strikes and inflicts status abnormalities.
Lightning will also run into Yeul from Final Fantasy XIII-2 who begs her to save Caius. Caius and Lightning clashed before in Valhalla, but Lightning didn’t fare so well during that fight. Caius he holds the heart of Etro, the goddess of death within him, and released the Chaos energy when Serah and Noel fought him.
Academia (left) has seen better days. This was a thriving town in Final Fantasy XIII-2, but it crumbled to ruins in Lightning Returns. Valhalla (right) can be found in a corner of the Wildlands. Followers of Etro live there. Noel the "Shadow Hunter’s" hideout is below with words written in blood and the Warren, a slum where a cult called the Children of Etro is to the right.
One of Lightning’s quests in Luxerion is to track down a serial killer. She investigates and finds flyers left by the culprit. Her investigation leads her to the Children of Etro… who come in handy and block Noel when he pursues Lightning.
Lightning has to fight Snow, Serah’s husband and ally in Final Fantasy XIII. Snow has a few tricks up his sleeve. While he still uses his fists, his fists are charged with ice and chaos power.