Sup guys. Im gonna keep this build/ guide short and sweet. Vel'Koz is a frigen amazing APC. He is a solo lanner who counters a lot of people. He is really good at countering anyone with a stationary ult. His whole purpose is to initiate and land fast and strong combos to chunk the enemy.

Vel's passive is what chunks your foe. Organic Deconstruction is his passive in which if you place three marks of deconstruction on them. Your marks have a timer in which you can refresh if you hit them with your Standard Attack. Your Q shoots a ball that splits in two at the end of its cast range, slowing enemies hit by them. You can press Q again to split it early using geometry to poke or last hit your opponents. His W creates a Void Rift, dealing damage and slowing enemies hit. After a short delay, a second wave damages the enemy. Your E Tectonic Disruption launches all enemies in the range up into the air and stunning them. It also grants vision to area cast. Finally your R Life Form Disintegration Ray shoots a beam of energy that follows your cursor for a short time dealing AP damage and true damage based on Organic Deconstruction. It also slows and adds Organic Deconstruction marks every .5 seconds. When you combo your enemy you want to use your E then follow with your W. Dealing AP damage and True Damage. Then use your Q to slow and add an Organic Deconstruction mark. Then finish them off with your R to Melt them and chunk them with your twice with your Organic Deconstruction.

Pros
Amazing solo laner
Great in team fights
Has good crowd control
Chunks really fast
Can kite like a Boss
Cons
So frigen Squish
Way mana hungry
Combos hard to land
Has no true escape

Thanks for reading. Hope it was short and sweet. My last word of advice is don't die in mid lane and have fun. If you liked please Vote for!!!