Dogs of War are troops of other races who are prepared to fight under your flag in return for money, food, or some other suitable reward. The most common type of Dogs of War unit are the Regiments of Renown. Although the two terms are used to describe mercenary units, both work in the same way in the army list. A selection of such regiments are available as part of the Dogs of War range of models. The descriptions and rules for these very specialised units can be found in White Dwarf magazine or the Warhammer Annual.
The option to include Dogs of War units is included in the army list as part of the Rare troops section. However, certain Regiments of Renown are more commonly available and can be included in an army as a Special choice instead of a Rare choice. Some Dogs of War may also take up additional Rare choices, or choices from your Character entries. The rules for individual Regiments of Renown detail exactly which armies may take them and which army list choices they use up.