Kinda dragged. Yeah, I know there's an in-game reason for that, but while I didn't figure out everything before hand, it feels like it takes sooooooo long to establish that he stood on top of the Ama-Pal's head.
They also try to make it sad at the end, especially how Yuma has to kill him, but Yuma having to kill the girls in chapter 2 was way sadder, especially since Yakou was already dead. Speaking of, why couldn't they kill Yomi with the labyrinth? He contributed to the murder about as much as Yoshiko did in chapter 2.
Vivia's pretty solid. His sleepy gimmick isn't that great, but he was enjoyable here as the smart guy trying to protect Yuma's feelings.