Abilities

Abilities are unique skills that Heroes and creeps have access to on the battlefield. They range from simple passive effects, to devastating explosions of energy, to complex, terrain changing feats. All Heroes have four or more abilities, three or more basic abilities and an ultimate ability, that they can assign ability points to every time they level up. Every level in an ability makes it more powerful, sometimes increasing its mana cost as well.

Abilities can consume mana, and may also be placed on cooldown when used. Abilities that are on cooldown can not be used until their cooldown timer is up, at which point they can be cast again. Abilities with low cooldowns are sometimes referred to as "spammable" abilities, because they can be used very frequently.

Upgrading Abilities
Every time a Hero levels up, they earn an ability point which they can use to upgrade any of their abilities, learn a new ability, or can be used to upgrade their. At the start of the game, Heroes know none of their abilities, but are given a free ability point to learn one. Abilities cannot be used and do not have any effect if they have not been learned. After an ability is learned, it can be upgraded three more times, for a total of four levels. The exception is a Hero's ultimate ability, which can only be upgraded to level 3.

Basic Abilities
Basic Abilities can be upgraded to a new level once every 2 levels. This means that a level 2 Hero cannot upgrade a learned ability to level 2. The same requirement applies to the. Every 2 levels, a Hero increases his maximum ability level by 1. Ultimate abilities can only be upgraded every 5 levels, starting from level 6. These abilities are usually more powerful than a Hero's basic abilities.

Upgrading abilities will make them more powerful, or capable of doing more powerful things. Sometimes, upgrading abilities will also increase their mana cost. For example, each level in Earthshaker's increases the damage it deals and the duration of its stun, but increases its mana cost by 15 per level.

Ultimates
A Hero's last ability, which can be trained at level 6, level 11, and level 16, with the exception of Invoker's (which can be trained at levels 2, 7, 12, and 17), and Meepo's  (which can be trained at levels 3, 10, and 17) is called an Ultimate. In general, ultimates have long cooldowns due to their sheer impact and effect and often have the potential to be a game changer. Earthshaker's  and Sand King's  are examples of such. Hero ultimates can be an active ability or a passive ability.

Among ultimate abilities, there are some ultimates which don't have a particularly long cooldown such as Sniper's, Pudge's , Invoker's , and Slardar's. Some ultimates, while being active abilities, don't even have a cooldown, such as Leshrac's, Tinker's , Enchantress's , Storm Spirit's , and Pugna's as improved by Aghanim's Scepter.

Some heroes also have passive ability ultimates which greatly enhances the hero's capability in their role, such as Drow Ranger's, Meepo's , and Tiny's. Wraith King's is a unique ultimate where it is a passive ability by nature but has a cooldown and mana requirement typical of an active ability. Other ultimates have passive and active parts, like Slark's which must be cast, but can also provide regen depending on whether the hero is in enemy vision.

Ultimates, unlike normal abilities, are usually able to target a unit under a spell immunity effect, such as Black King Bar. They will rarely damage such a unit, but other effects such as slows or stun will generally apply. This makes ultimates, especially those with stun effects, incredibly powerful, since enemy Heroes cannot block the effects. However, there are exceptions such as Tidehunter's which cannot affect enemies with spell immunity.

On many heroes an Aghanim's Scepter will buff the heroes' ultimate ability. Typical examples of the effects of Aghanim's Scepter on a hero's ultimate are an increased damage/duration, or a decreased cooldown/cost. In the instance of Ogre Magi, a new ability can be gained. Other times, heroes will gain the effect of one of their other abilities, such as Spirit Breaker's performing an AoE of, or Silencer's  applying the current level of. Rubick is the one hero where obtaining a Aghanim's Scepter is recommended based on the opposing hero line-up due to the fact that any stolen ultimate is upgraded, regardless of whether or not the target has Aghanim's Scepter.

Charge based abilities
Some abilities (basic and ultimate abilities) do not use the cooldown system, but instead have a number of charges and no cooldown. Each cast of such spell consumes one of its charges, which then replenishes over time.

Ability Types
An ability's type refers to how that ability's effects are applied.

Active
Active abilities must be used in order to apply their effects. Active abilities can consume mana, have cooldowns, and usually have some method of targeting related to them. The majority of abilities are active abilities. Active abilities are indicated by a bevel around the icon, which makes them look like a button. They can be activated by pressing their associated hotkey, and double tapping the hotkey can cause them to activate immediately on the caster.
 * Examples of active abilities are Weaver's, Ursa's , and Necrophos's.

Passive
Passive abilities apply their effects either permanently as soon as they are learned, or activate by themselves if the ability is learned and its requirements met. These requirements can range from attacking a unit, casting a spell or even getting attacked. Most passive abilities do not consume mana and usually don't have Cooldowns, exceptions include Wraith King's. Most Heroes have at least one passive ability, though not all do.
 * Examples of passive abilities are Wraith King's, Crystal Maiden's , and Drow Ranger's.

Autocast
Autocast abilities are special abilities that can be toggled on or off, or manually cast. Most auto castable spells are active attack modifier, applying a modification to the user's attacks when activated. When toggled on, the ability will apply when it can. For example, Drow Ranger's will be used whenever she attacks a target. When toggled off, they will not be used and will not consume mana. When an active attack modifier is manually cast, it partially is treated as a spell cast, instead as an attack. This causes nearby enemy creeps to not aggro when using them that way. This is also known as orb walking.

Not all abilities with autocast are attack modifier. A few of them are regular abilities, which, when toggled on, will automatically cast when their requirements are met. An example of such is Ogre Magi's. When toggled on, Ogre Magi will automatically cast Bloodlust on an attacking allied hero.

These are the only auto castable active attack modifier:
 * Clinkz's
 * Drow Ranger's
 * Enchantress's
 * Huskar's
 * Outworld Devourer's
 * Silencer's
 * Tusk's
 * Viper's

And these are the only auto castable active abilities:
 * Hill Troll Priest's
 * Lich's
 * Ogre Magi's

Targeting Types
Active abilities and autocast abilities are targeted in different ways, depending on the effects of the ability.

No target
Abilities with the no target requirement are immediately cast as soon as its button is pressed. Many of these abilities do not have a cast time. They cannot directly target a unit or a point. They usually affect the caster, or units around the caster. They can affect an area around the caster, or have a global effect.
 * Examples of instant abilities are Mirana's, Slardar's , Pudge's , and Zeus'.

Target Point
Point target abilities require the caster to target a point or an area. Upon pressing such spell's button, the cursor turns into a crosshair that determines where the ability will be cast, or in which direction it will be cast. Point targeting abilities can have very varying effects. For some spells, it merely determines the direction to launch an effect, for other spells it determines an exact point where an effect will be applied.


 * Examples of point target abilities are Nature's Prophet's, Spectre's , and Morphling's.

Target Area
Area target abilities work pretty much like point target abilities, with the only difference being that they require the caster to target a whole area, instead of a point. Upon pressing such spell's button, the cursor turns into a tarageting reticule which shows the area the ability will effect. Upon cast, these abilities usually affect the whole targeted area, or all units in the area. Some apply their effects once upon cast, some apply a lasting effect which affects units which enter the area after cast.


 * Example of area target abilities are Crystal Maiden's, Alchemist's and Faceless Void's.

Target Unit
Unit target abilities require the caster to directly target a unit, and cannot be used on the ground. Upon pressing such spell's button, the cursor turns into a crosshair that determines on which unit the ability will be cast. Most unit targeted abilities affect only the target. Some abilities require to target a unit, but affect an area around the unit. Abilities that apply their effect to a single unit are often called "single target spells". When targeting a unit which is out of cast range, the caster will follow the unit, until it gets in cast range or can't be targeted anymore (e.g. the target turns invisible).
 * Examples of unit abilities are Lina's, Sven's , and Omniknight's.