Battle Royale: v. 9 by Koushun Takami
Shuuya is alive, and being nurtured back to health by another group which has also joined forces to escape. This group consists only of girls and they've taken up residence in the island's lighthouse. Meanwhile, Sugimura continues his search to find Kayoko but meets up with Kiriyama again. At the lighthouse, all hope turns to despair as Yuko's paranoia makes her believe Shuuya is the Devil. Yuko's attempt to kill Shuuya fails but it ends up turning the girls against each other.