Cleave is the warrior's first multiple target attack, learned at level 24. It is also used by many high-level bosses that mainly use physical attacks. It is a 30 Rage skill that deals weapon damage plus a small bonus to two targets: the current targeted mob/player and their neighbor.
Currently, Cleave is the only multi-targeted Warriorability that both scales with weapon damage and can be used while in [Defensive Stance], and the only multi-targeted ability of any class that does not trigger a Global Cooldown. This makes it ideal for high-end tanking situations involving multiple targets.
Cleave, like [Whirlwind], may be combined with [Sweeping Strikes] in order to generate additional hits. Cleave's secondary target is the nearest enemy other than the Warrior's main target. For this reason, if the Warrior and all targets are stationary, Cleave will continue to strike the same secondary target. Shifting positions slightly will often change the secondary target, however tanks and dps alike should be aware that this may cause Cleave to break nearby CC if not used carefully.
Though the tooltip states that the secondary target of the Cleave will be the primary target's nearest ally, it instead appears to affect closest enemy target, regardless of whether it is allied with the primary target or not. For example, if a Warrior were to Cleave a monster standing near an NPC of the opposing faction, the cleave would affect the enemy NPC as well, though it is not allied with the primary target.
Cleave is very similar to [Heroic Strike] and a lot of the same tactics can be applied. Generally, Cleave should be used like Heroic Strike but only in AOE situations in order to not break CC and limit aggro to the tank's main target.
For a more in-depth discussion of the mechanics and mathematics of Cleave, refer to the Talk:Cleave/Analysis page.
Patch changes
Patch 4.0.3a (2010-11-23): Damage has been reduced by approximately 17%.