When you are playing with the Wachhündchen/Wachhund (Watchdoggie/Watchdog, character value -2), the following rules apply:
As long as the Watchdoggie/Watchdog is alive, the Mayor can´t be lynched. The Watchdoggie/Watchdog can be lynched, or killed by the Werewolves or by other night effects.
You can only play with the Watchdog if you openly award the mayor by majority vote at the start of the game. Give the watchdog to the player who plays the mayor. As long as the watchdog lives, the mayor can not be lynched during the day.
If the current mayor dies in a different way and the guard dog is still alive, the player must immediately pass on the mayor's card and watchdog's card to another surviving player without discussion. The watchdog can be eaten, lynched, shot by the hunter or poisoned by the witch. The healer can heal the guard dog to protect him from the werewolves attack. But beware: There may be a werewolf behind the mayor.
Complete instructions on www.pegasus.de/werwoelfe
—description from the publisher