Hello! Hello! Hello! Welcome to my AP VARUS Guide. I know what you are thinking. WTF VARUS IS AN ADC. WHAT A TROLL THIS ISNT GOING TO WORK ARGHHGJGJGJGJGJGJGJ! Well, thats what I am seeing. Anyway Varus mid as an ap carry is a extremely fun role to play. It is even more fun when they laugh when they see an ap varus, then get raped by him! :D

AP Varus is not a joke. It is a very effective, high burst ultra-carry late game. He is probally one of the most fun mids I have played, simply for the fact of his playstyle. His playstyle is nicely described by me as a mix between Teemo and Darius. WHAT?!?!? I will explain later. :D

This is easy. You rely on his W: Blighted Quiver. What this does is once activated with any stacks of blight by any other ability, the target takes AP damage based on max health. This is scales with ap fairly good. This is your source of damage. With no AP at all, rank 5, one auto attack and an ability use take 5% of the targets max health away. Two and it is 10%, three and it is 15%. This can eventually scale up to 15% per stack, which detonating with 3 stacks and BOOM. 45% of their health. GONE FOREVER. This is why I compare him to darius. They both need to get stacks off before they can do sufficient damage. His ult also scales off of ap (1.0 Extra Damage Per AP) which is very nice for teamfights. His autoattacks from his W also scale off AP which combined with Malady and Wit's End keep you doing damage even before you are able to pop an ability.

PROS

Very Strong Late Game
Ult does even higher damage
Can Poke Very Hard
Difficult to 1v1 late Game
Extremely Fun!

CONS:

Very Squishy
Little damage early game
Item Reliant
Can't Fully do proper damage until level 6
Not taken seriously

Runes here are pretty basic.
Basic Scaling MR
Magic Pen Reds to help burst with from abilities
Ap Quints used for early game damage
Basic Armor

Maxing your correct skills is pretty basic but I will give you the rundown.
R>W>Q>E
Max your ultimate first obviously.
Max W second because that is a majority of your damage and maxing it will give you more burst.
Max Q third for increased poke.
Max E forth.

You want to let the tank engage first. DO NOT USE YOUR ULT TO ENGAGE. You are losing an activation for your W and it can be wasted. When the tank engages, focus the carry and try to get 2-3 stacks of blight off BEFORE you ult. Then your ult cant begin to damage everyone as you begin to put more and more stacks on their team. Also, do not charge q at full range. Quickly hit it to get it off to quickly detonate blight.

Sorry for such a short guide. It is my first one and I hope to add more and more to it based on feedback. Varus is a good adc but an even better AP mid with tremendous burst damage. Try him out!