The Fellowship of the Ring Werewolf

[Frank the Tank]

He could watch a non roled player who doesn't do an action because there are none to do

 
Or someone who only has day actions

From the OP, all actions are night actions.

Day Phase - 10am−9pm: This is the voting phase. Players discuss, debate, and vote to lynch one person they suspect is a Wolf. The person with the most votes is eliminated from the game.
Night Phase - 9pm−10am: The GM receives private messages from players with special roles. The Wolves choose their target, the Serial Killer chooses theirs, and any special actions are carried out.