What happened to Muroi in Shiki? As the series progresses,


  Muroi allies with Sunako and her "family". In the final scenes, we see him get on a car with a briefcase containing Sunako.  Did he become one of the "Daywalker" Shiki, or did he just remain a human?
At the end of the series, 


   he's bitten by Sunako, then becomes the only surviving day-walker, and then is seen smuggling Sunako away. Presumably, he'll accompany Sunako either in hiding or to find another village to turn into a Shiki village.