Welcome to Vel'koz 101. He is so op mid to late game and ok early but please be very careful early cause he is super squishy. He is a solo laner but can supp well but is not recommended. You have to time all of his abilities and summoner spells correctly and aim his q right. It's not easy but when you get use to him it gets easier. So lets jump on in and learn about Vel.

Mr = Magic Resist
Ap = Ability power
Op = Over powered/ing
Ad = Attack Damage
C = Carry

It's 21/9/0 because he needs all the ap he can get. I choose defense tree over the utility tree cause he needs armor and mr.

These runes help him sustain a little but not much. They do however let you run over your opponents, because of his low mobility and squishiness he can win by playing passively and later on by staying back in team fights harassing and waiting to activate his ult ether its to get a kill or to assists.

These items keep up your AP and make you so op. Again you are squishy and easy to kill. All you need to do is play Passive-Aggressive. For those who don't know what this means you stay behind your allies and harass your enemies until they are low on health which is when you jump in and take the kill(s).