W is for War Beast.
(They're hard to control.)
Charging straight at the enemy,
'cause that's how they roll.
From F is for Fanon: an Unofficial Lexicon
War Beasts are a class of unit. Some are humanoid in form, but none are sapient. There are two types of War Beasts: Greater War Beasts and Lesser War Beasts. Most sides that can pop War Beasts are limited to popping either Greater War Beasts or Lesser War Beasts; almost none can pop both. As a result, all War Beasts tend to be referred to as "War Beasts," unless examples of both types are present.
Greater War Beasts are powerful and dangerous units and tend to be heavies. In addition, many of them also have to be physically restrained when not in battle, which may be indicitive of a low obedience; this, in turn, may cause them to either attack without orders or pose a physical danger to their own side. They radiate malice and hostility and it is extremely difficult to get them to stop fighting once they have engaged in combat. Greater War Beasts are frequently used as shock troops due to their ferocious combat capabilities. Due to their long production time, high upkeep and the inherent difficulty in controlling them, even sides that can pop them tend to do so in relatively small numbers.
Lesser War Beasts are usually not heavies. While no less vicious, these Lesser War Beasts tend to rely on large numbers to compensate them for their relatively weak abilities. They also require fewer turns to pop and less upkeep, allowing a side to afford several Lesser War Beasts for the cost of one Greater War Beast. They tend not to need restraining between battles, but have similar control problems when battle is joined.
War Beasts can be kept under control when stacked with a Warlord who posesses the Beastmaster special rule, substituting the Beastmaster's obedience over their own. This is accomplished through a form of Natural Thinkamancy, which also allows the Warlord to see through the eyes of War Beasts within a specific range of the Beastmaster's position.
Despite their inherently unpredictable and dangerous nature, a few sides are War Beast dependent, popping even Greater War Beasts in large numbers. These sides either pop large numbers of Beastmasters to keep their War Beasts under control or deliberately rely on the anarchic nature of War Beasts to sow chaos among enemy forces, hoping that foes will not be able to predict the nature of the attack they face. These sides tend to be heavily outnumbered in battle and, when part of an alliance, tend to form the vanguard of any attacking force.
Non-humanoid Greater War Beasts may be used as mounts by warlords with the Beastmaster special. Lesser War Beasts and humanoid Greater War beasts may not be used as mounts by any unit.
 Known War Beasts
Greater War Beasts:
Lesser War Beasts: