Ultimate

Ultimate
A Hero's last skill, which can be trained at Level 6, Level 11, and Level 16, with the exception of Invoker's Invoke(which can be trained at levels 2, 7, 12, and 17), and Meepo's Divided We Stand(which can be trained at levels 4, 11, and 18). 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 Echo Slam and Sand King's Epicenter are examples of such. Hero ultimates can be an active skill or a passive skill.

Among ultimate skills, there are some ultimates which don't have a particularly long cooldown such as Sniper's Assassinate, Pudge's Dismember, Invoker's Invoke, and Slardar's Amplify Damage. Some ultimates, while being active skills, don't even have a cooldown, such as Leshrac's Pulse Nova, Tinker's Rearm, Enchantress's Impetus, Storm Spirit's Ball Lightning, and Pugna's Life Drain as improved by Aghanim's Scepter.

Some heroes also have passive skill ultimates which greatly enhances the hero's capability in their role, such as Riki's Permanent Invisibility, Drow Ranger's Marksmanship, Meepo's Divided We Stand, and Tiny's Grow. Skeleton King's Reincarnation is a unique ultimate where it is a passive skill by nature but has a cooldown and mana requirement typical of an active skill. Other ultimates have passive and active parts, like Slark's Shadow Dance 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 magic 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 Ravage which cannot stun enemy with magic immunity.

On many heroes, Aghanim's Scepter, when purchased, will give a strengthening effect to the hero's ultimate ability in addition to the stats it provides. 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 skill can be gained. Other times, heroes will gain the effect of one of their other skills, such as Spirit Breaker's Nether Strike performing an AOE of Greater Bash, or Silencer's Global Silence applying the current level of Curse of the Silent. 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.

Aghanim's Scepter
Improves the ultimate of some heroes