Of course, the Warhammer world is a place of magic, of spell crafted armor and magical protection, where creatures can have an arcane resilience at odds with a sometimes frail appearance. For such circumstances we have the ward save. A ward save represents some form of magical protection, be it a spell, enchanted armor or perhaps even the innate nature of a Daemon or other magical creature. Ward saves are not necessarily represented by a model's equipment – unbound by physical laws, Daemons and their ilk have no need to burden themselves with weighty armor, for example.
The value of a ward save will always be shown in a model's entry in the relevant Warhammer army book. Daemons, for example, have a ward save of 5+, meaning that a score of 5 or more is required to prevent a wound. The key difference between ward saves and armor saves is that ward saves are never modified by the Strength of the attack. Just as with armor saves, a roll of a 1 is always failure, however good the save.
Note that different ward saves cannot be combined to increase a model's chance of saving. If a model has more than one ward save, simply use the best.