Several armies can include daemons of which the most common by far are the armies of Chaos. Rules for Chaos daemons are covered in complete detail in the Realm of Chaos Warhammer Armies book. However, because daemons are quite interesting monsters that other warriors may have to fight, the rules are also given here.

Most daemons fight in units of several models in the same way as Men, Elves and other mortal troops. Greater Daemons are the largest and most powerful daemons just as mighty characters are the most powerful members of their race. Greater Daemons are considered to be characters, and the rules applying to character models also apply to Greater Daemons. For example they can fight on their own as units of one model, and they can issue and meet challenges.