Viper/Guide

General

 * and slow attack speed as well, apply them to the enemy carry to cripple their damage output.
 * Viper is great at kiting melee carries with his large variety of slows and with an.
 * More tips needed.


 * Primarily leveling Poison Attack is the best way to slow and damage a target of your choice and doesn't require your opponents to attack you for the ability to be applied. If you're in a lane with supports, this is probably the strongest choice.
 * More tips needed.


 * Nethertoxin is generally the last ability to level, but if the rest of your team is capable of getting your opponents to low HP quickly, this will allow you to easily clean up fights. It's a good choice to pick up early if you want to last-hit easier.
 * More tips needed.


 * Corrosive Skin is the best choice to max first if you'll be in situations where you and your opponent(s) will be trading blows, rather than you just attacking. The damage per level of this ability is roughly the same as Poison Attack, but greatly increases how tanky you are.
 * Corrosive Skin is especially potent against DoT spells. Between the magic resistance and continuous reapplication of Corrosive Skin to the caster of the DoT, Viper will usually take less damage than Corrosive Skin returns.
 * More tips needed.


 * Viper Strike is one of the best ganking abilities in the early game. Remember to take advantage of this.
 * With an early aghanims scepter viper strike could be the best ability to start teamfights as its cooldown would be low

Items
Starting:
 * helps Viper stay in lane.
 * adds to Viper's last hitting ability in the early game.
 * increases Viper's stats.

Early Game:
 * is required on all heroes.
 * provides a decent boosts to Viper's stats.

Core:
 * are the boots of choice to augment Viper's DPS and increase his tankiness.
 * gives Viper a decent boost in damage, which helps with last hitting, and can be upgraded to a.
 * is a strong defense item that does a better job than, and the active heal is useful for both yourself and your teammates.

Situational:
 * allows Viper to cast his ult it in teamfights more than once which lowers his target's DPS, slows them, and deals a hefty amount of damage. It also increases his tankiness, and Viper's usefulness goes up greatly the longer he's in a fight.
 * gives all-around stats which will all benefit to Viper. Dragon Lance alone is like a cheap, allowing to often initiate on a single target from far away, slowing him with the Poison Attack only. Less efficient than the ultimate, however the active allows to either reach the target faster, or run away from it while still being able to hit in dangerous situations. All-in-all, a very good multi-purpose situational item.
 * is a worthwhile upgrade from Dragon lance.
 * is another item that provides a mix of damage and tankiness. Once you have a solid HP pool, evasion makes Viper much, much harder to bring down with physical damage.
 * provides an unreliable disable on top of a solid chunk of damage. It's best if your team is low on disables or enemy carries are picking up evasion.
 * improves Viper's damage and gives mana burn. The active can purge enemies.
 * is a good pickup on Viper if you intend to use it for ganking. Viper is a very capable ganker if he can get into close range with a target. Between both of his slows and his damage scaling up as his target's health decreases, Viper is a very good hero for dueling.
 * provides a mix of tankiness, damage, and chasing potential, all which greatly help Viper. It also provides a way to remove certain debuffs.
 * prevents spellcasters from using disabling spells, as well as making your targets more vulnerable to your DPS. The mana regeneration also remedies Viper's constant lack of mana.
 * increases Viper's tankiness, and combined with your Corrosive Skin and a, Viper will be incredibly hard to put down.