So, here, a daemon is a meddling spirit, associated with a particular game object, which gets a chance to interfere once per turn while it is 'active'. Each object can have a daemon routine of its own. Daemons are often started by a game's Initialise routine and sometimes remain active throughout. In particular, a daemon doesn't stop running just because the player has moved on to somewhere else. Actually this is very useful, as it means daemons can be used for 'tidying-up operations', or for the consequences of the player's actions to catch up with him.
Many games contain 'wandering monsters', characters who walk around the map.
Use a daemon to implement one who wanders as freely as the player, like the gentleman thief in 'Zork'. It should allow for feathers to be lighter than lawn-mowers. There is yet a third form of timed event. Each turn' is especially useful to run creatures which stay in one room and are only active when the player is nearby. Nearby' actually means 'in scope', a term which will be properly explained later.