Dota 2/Invoker

Invoker is a ranged intelligence hero that has a very unique skill set. His can give himself constant buffs by controlling his 3 different elements, giving him health, damage, speed or a combination of any of them. His most notable feature is his Invoke, which will combine his elements to form up to 10 different abilities. He can use these abilities to buff, harass, disable, assassinate and escape. This means that Invoker can be a very versatile hero, but the amount of abilities he has means that a player must be able to know which ability to Invoke for the current situation, making him one of the hardest heroes to be played at his full potential.

Leveling System
Invoker has a unique leveling system different from other heroes. He cannot level up his attribute bonuses, instead he gains bonus stats by leveling up his 3 elements Quas, Wex and Exort, which can be leveled up to 7 times. His ultimate, Invoke, can also be leveled up 4 times instead of 3, at the levels 2, 7, 12 and 17.

Quas
Quas lets you manipulate ice, which gives you bonus health regeneration for every instance of it as well as passively giving you a permanent strength increase.
 * Ability: No Target
 * HP Regen Per Instance: 1 / 2 / 3 / 4 / 5 / 6 / 7
 * Bonus Strength: 2 / 4 / 6 / 8 / 10 / 12 / 14

Wex
Wex lets you manipulate lighting, giving you increased attack speed and movement speed for every instance as well as passively granting you bonus agility.
 * Ability: No Target
 * Attack Speed Per Instance: 2% / 4% / 6% / 8% / 10% / 12% / 14%
 * Move Speed Per Instance: 1% / 2% / 3% / 4% / 5% / 6% / 7%
 * Bonus Agility: 2 / 4 / 6 / 8 / 10 / 12 / 14

Exort
Exort lets you manipulate fire and makes your attacks do more damage for every instance as well as passively giving you bonus intelligence.
 * Ability: No Target
 * Damage Per Instance: 3 / 6 / 9 / 12 / 15 / 18 / 21
 * Bonus Intelligence: 2 / 4 / 6 / 8 / 10 / 12 / 14

Invoke
Invoke lets you combine the 3 elements you currently have to create a new ability. as there are 3 elements and you can have up to 3 instances of elements you can create a total of 10 different spells. These new abilities will be detailed below.
 * Ability: No Target
 * Max Spells: 1 / 2 / 2 / 2
 * Mana Cost: 20 / 40 / 60 / 80
 * Cooldown: 22 / 17 / 12 / 5
 * Scepter Mana Cost: 0
 * Scepter Cooldown: 16 / 8 / 4 / 2

Aghanim's Scepter can be bought by Invoker and will remove Invoke's mana cost as well as reduce its cooldown.

Cold Snap
Cold Snap is invoked with 3 Quas instances. It deals damage as well as briefly stuns the targeted unit, then causing any damage taken by the unit to stun it again. There is a very slight cooldown between the stuns and the debuff itself has a set duration, which is affected by the level of Quas you have. It is a very annoying harassment tool, and can be a deadly disable when ganking or chasing as any instances of damage will stun the enemy.
 * Ability: Target Unit
 * Affects: Enemy Heroes
 * Damage Type: Magical
 * Initial Damage: 60
 * Freeze Duration: 0.4
 * '''Bonus Damage: 30
 * Mana Cost: 100
 * Cooldown: 20

Ghost Walk
Ghost Walk is invoked by having 2 Quas instances and 1 Wex instance. It renders Invoker invisible as well as slowing nearby enemies based on his level of Quas, but also slows yourself based on the level of Wex. A good escape tool even though it does slow you down, though once your Wex gets above level 4 you will always be slowed less than your enemies, with the self-slow nonexistant at level 7. It can also be a funny way to slow your enemies by walking near them to hinder their escape, slowing them without them even realizing the cause.
 * Ability: No Target
 * Radius: 400
 * Duration: 100
 * Mana Cost: 200
 * Cooldown: 60