Dota 2/Viper the Netherdrake

Viper is a ranged agility hero that is usually played as a carry. Despite his average health he can be quite durable with his Corrosive Skin. Viper can do more damage the lower an enemy's health with his Nethertoxin. He can use his Poison Attack to slow enemies down as well as poisoning them. His ultimate, Viper Strike, is one of the best slows in the game, slowing enemies to a crawl.

Poison Attack
Poison Attack is a toggled ability that makes your normal attacks slow enemies as well as do damage over time. It is a Unique Attack Modifier and will not stack with other Unique Attack Modifiers. While it can be auto-cast to apply the effects to your attacks as long as you have mana, it is not reccommended since you will make creeps attack you and possibly run out of mana quickly. A good ability to harass opponents or to simply chase down dying enemies.
 * Ability: Auto-Cast, Target Unit
 * Affects: Enemy Heroes
 * Damage Type: Magical
 * Duration: 2
 * Damage Over Time: 10 / 16 / 22 / 28
 * Move Slow: 10% / 20% / 30% / 40%
 * Attack Slow: 10% / 20% / 30% / 40%
 * Mana Cost: 20
 * Cooldown: 4 / 3 / 0 / 0

Nethertoxin

 * Ability: Passive
 * Damage: Physical
 * Base Bonus Damage: 2 / 4 / 6 / 8
 * Non-Hero Damage: 50%
 * Max Bonus Damage: 32 / 64 / 96 / 128

Corrosive Skin

 * Ability: Passive
 * Damage Type: Magical
 * Durarion: 3
 * Move Slow: 10% / 15% / 20% / 25%
 * Attack Slow: 10% / 15% / 20% / 25%
 * Magic Resistance: 10% / 15% / 20% / 25%
 * Damage Over Time: 10 / 15 / 20 / 25

Viper Strike

 * Ability: Target Unit
 * Affects: Enemy Heroes
 * Damage Type: Magical
 * Duration: 5.1
 * Damage Over Time: 60 / 100 / 145
 * Move Slow: 40% / 60% / 80%
 * Attack Slow: 40% / 60% / 80%
 * Mana Cost: 125 / 175 / 250
 * Cooldown: 80 / 50 / 30
 * Scepter Cast Range: 800
 * Scepter Mana Cost: 125
 * Scepter Cooldown: 12