Dota 2/Zharvakko the Witch Doctor

Witch Doctor is a ranged intelligence hero who is usually played as a support. He has a variety of damage spells and disables, and possesses a very good heal. His Paralysing Cask can bounce between enemies, which makes it quite powerful when it catches a few lone enemy heroes by themselves. He is also a valued ally due to his Voodoo Restoration, being a toggled heal that he can keep active provided he has enough mana. His Maledict and Death Ward are all deadly area of effect spells. Maledict will do more and more damage the longer the enemy is cursed with it while Death Ward will shred enemy heroes apart, as long as you're not interrupted while channeling it.

Paralysing Cask
Paralysing Cask deals damage and stuns the target, and will bounce to a random nearby enemy unit doing the same thing. Although it is a mediocre stun when used on a lone enemy or in a group of enemies, if you manage to only catch two enemy heroes with this ability, it will bounce back and forth between them, dealing a lot of damage and stunning them repeatedly. Even if you do catch more than 2 enemy heroes, the stun is still good enough to potentially net your team a kill. It can also be used for pushing, as the bouncing cask will clear out a bunch of creeps.
 * Ability: Target Unit
 * Affects: Enemy Heroes
 * Damage Type: Magical
 * Damage: 75 / 100 / 125 / 150
 * Hero Stun Duration: 1
 * Creep Stun Duration: 5
 * Hero Damage: 50
 * Bounces: 2 / 4 / 6 / 8
 * Mana Cost: 110 / 120 / 130 / 140
 * Cooldown: 20 / 18 / 16 / 14

Voodoo Restoration
Voodoo Restoration heals all nearby allies when toggled on, though it costs mana to both activate it and maintain it. However, it can be used as long as you have the mana to keep it going. Despite the expensive mana costs, it is a very useful heal. You can heal up your allies before or after a major push or fight, or just run around during a teamfight keeping your allies alive.
 * Ability: No Target, Toggle
 * Mana Per Second: 8 / 14 / 20 / 26
 * Radius: 375
 * Heal: 16 / 24 / 32 / 40
 * Mana Cost: 25 / 50 / 75 / 100

Maledict
Maledict curses all enemy heroes in the targeted spot, causing them to take damage every 4 seconds. They will also take bonus damage for every 100HP they lost since they were cursed. It might seem weak at first glance, but as more health is lost on the cursed hero, the bonus damage becomes a real threat. For example, at level 4 it can do 140 damage in one instance if the target has lost 300 HP, which happens quite frequently when they take damage from other spells. If they still have 300 HP missing for the entire period of the curse they will take a total of 420 damage, so don't underestimate how powerful this spell can become.
 * Ability: Target Point
 * Damage Type: Magical
 * Damage: 5 / 10 / 15 / 20
 * Bonus Damage: 16 / 24 / 32 / 40
 * Radius: 150
 * Duration: 12
 * Mana Cost: 120
 * Cooldown: 35

Death Ward
Death Ward summons a ward that has 700 range and will attack once every 0.25 seconds for 8 seconds, doing a lot of damage to enemy heroes. The ward can't be destroyed unless you are interrupted or die and you can make it target a specific hero. It will bounce to another hero once at level 3. The damage it deals is ridiculously high, enough to shred weaker heroes and greatly soften up carries. Since it's a channeled ability, you have to make sure you don't get hit by a mini-stun, or you'll stop the spell early.
 * Ability: Channeled, Target Point
 * Damage Type: Physical
 * Damage: 60 / 90 / 120
 * Mana Cost: 200
 * Cooldown: 80
 * Scepter Damage: 90 / 120 / 150

Aghanim's Scepter can be bought by Witch Doctor and will increase the damage dealt by Death Ward as well as make its shots bounce once at level 2 and 4 times at level 3.