Varus
The Arrow of Retribution
I use this build for my often 3v3's but can be used in 5v5 with the addition of Summoner Spell Smite and removal of Summoner Spell Exhaust. This build may be unique for me but should work for
you also. I hope that you enjoy this build and that it works wonders!

Rush the Doran's Blade! Kill off your foes with grace! Grab your Berserker's Greaves and hurry back to your lane! Run fast and strike hard while you grab your Zeal! You must be getting easier to take down so grab a Vampiric Scepter and steal their life force! Move faster and strike harder after your Phantom Dancer has been purchased! Grab your Bloodthirster to satiate your blood lust! Strike them down with your new, shiny Infinity Edge. You can't keep that lust down forever so grab another Bloodthirster. Your Doran's Blade is weak, replace it with another Phantom Dancer! Only then will you be the best of the best and ready to win!

Health Pots, Mana Pots, Wards, Etc. can be squished into the build when needed but is not recommended.

Runes

All to improve your damage output and reduce the effectiveness of their armor.
This will make you great at laning and won't plateau late game.

Masteries

Your masteries serve almost the same purpose as the Runes but also give some health and durability. This also will not plateau late game and will provide longer laning phases and less breaks taken for health.

Summoner Spells

Flash

Flash is great for chasing or escaping and allows you to run away from a 3v1 moment or chase an enemy down. Using flash takes practice and skill and isn't recommended for those who just gotten to the required level to use it.

Exhaust

Exhaust serves the same purposes as Flash but has a completely different effect. It decreases their damage output, movement speed, magic resist, and armor. They can't run after or away from you and cannot hurt you in anyway they could've before.

Smite

If you had chosen Smite over Exhaust then you would've been thinking you wanted to really jungle and not lane as much. Smite deals a lot of damage to a chosen Creep whether in the jungle or fighting large creeps or Tibbers is making you sad.

Focusing your Q is what makes Varus strong early game, while late game grabbing Blight and Hail of Arrows will make you very strong. At level 3, after you have all of your abilities, tag the enemy champion with as much Blight as possible and then use either your E or Q to deal the damage. Firing at them with your E while attacking them ill allow you to actually stack 4 Blight stacks on them. If you use your Q and let it charge completely you will end up taking at least 1/2 of their health. At level 6, once you grab your ultimate ability, you can really start taking them down. Your Chain of Corruption can hit all 5 of your enemies if they are close enough. It allows you to immobilize any enemy who threatens to kill you or your allies. It can also help you get a running champion by immobilizing them and allowing you and your team to catch up and grab the kill. At level 18 your famous combination of abilites will be, and remember this, Piercing Arrow, 3 stacks of Blight, Hail of Arrows, Piercing Arrow, and if needed, Chain of Corruption. This will obliterate your enemies and make them know that only the strong will survive.

Pros

He does a lot of damage very quickly
He has amazing range
He can get full health in 3 hits after full build
He has great attack speed
Short ulti cooldown
Great 1v1
Takes down tanks and high life creeps easily
Works well with an ally

Cons

He is squishy
He can't handle up close fights
A Quicksilver Sash will make his ulti very useless
If focused he is taken down very quickly
Can't take down multiple champions very easily on his own
Slow movement speed in the start of the game

I hope you enjoyed this and please leave comments to tell me how this could've been better or how much you really like/ hate this. :D I do this for you guys and you only so please don't hate just because you don't like an OP Varus!