Vel'Koz

Strengths

When laning, use Void Rift to kill minions while building stacks of Organic Deconstruction on your opponent. You can then follow up with your other abilities.
Shooting Plasma Fission diagonally and splitting at maximum range allows you to hit opponents that are out of the range of the initial missile, but is more challenging to pull off.
Be very careful about when to use Life Form Disintegration Ray. Many champions have abilities that can interrupt the spell.

Passive · Organic Deconstruction — Vel'Koz's abilities apply Organic Deconstruction to enemies on hit. If 3 stacks are accumulated, the enemy will take a burst of true damage.
Q · Plasma Fission — Vel'Koz shoots a bolt of plasma that splits in two on reactivation or upon hitting an enemy. The bolt slows and damages on hit.
W · Void Rift — Vel'Koz opens a rift to the void that deals an initial burst of damage, then explodes for a second burst of damage after a delay.
E · Tectonic Disruption — Vel'Koz causes an area to explode, knocking up enemies, and knocking close enemies slightly away.
Ultimate · Life Form Disintegration Ray — Vel'Koz unleashes a channelled beam that follows the cursor for 2.5 seconds that deals magic damage. Organic Deconstruction Researches enemy champions causing them to take true damage instead.

A suggested 5-lane lineup built around Vel'Koz, based on hero partnerships and role synergy — not win rate.