Aura

Auras are passive abilities that grant a buff or debuff to units in an area of effect around the holder, or in some cases, over a short period at a targeted point or unit. By default, the buffs and debuffs linger on the affected units for 0.5 seconds after leaving the radius, however, some auras have a different value. Aura buffs and debuffs are generally not dispellable.

Most auras cannot be controlled. They always affect units around the holder. Some auras can be toggled on or off. A few auras also have an extra active component, which range from temporarily boosting the aura to decide whether it should affect surrounding heroes only or not. The active components or the toggleability are treated like a regular spell, means they cannot be used or toggled while silenced or disabled. Beside these, there also are temporary auras, which are provided for a certain time period by casting a spell.

There is not set rule for which units are generally affected by auras and which not. It depends on the aura which units it affects and which not. If a unit does not meet the requirements for the aura, it is not affected. There are auras which affected only ranged units, or melee units, only heroes, or only non-heroes. As a rule of thumb, positive auras usually affect allied units (including the holder of the aura), while negative auras affect enemy units. There are a few exceptions.

Auras usually also affect invisible units, and units in the Fog of War. However, almost all auras do not affect invulnerable or hidden units.

Illusions can bestow most passive auras, but they usually do not benefit from them. Generally multiple auras of the same kind do not stack, but there are a few exceptions.