This isn't any Warwick. He's the CHOSEN ONE. A hybrid; Half Lycan, half Vampire.
His name is Barney. Hi Barney.

Before simply judging this build by the looks of it, actually try it.

Barney's creator's first build. Cut some slack.

Barney is aggressive. He suffers from ADHD.

His runes and masteries aid him in damaging the enemy through basic attacks and abilities by adding penetration, along with helping him survive through a pinch of vamp, plus his chill pills (Cooldown).

Basically, Barney is all about manipulation. His item builds are mostly on AP and Spell vamp.
Yes, barney likes Hextechs.

We build AP to help his spell vamp be more efficient. Why AP, and not AD?
His abilities do more damage raw, so why not stack it?
It's all about his Q and R. With cooldown reduction, high AP, mana, and decent spell vamp, Barney seems a bit invincible.

So what we do here is:
1. Farm
2. By 6, gank hard.
3. Build
4. Gank and Shank.

Your team must learn how to focus and target properly late game.
In team battles, Barney is built as a hitman. He rapes the focus, while he has AoE backing him. This is when the AP + Spellvamp kicks in. He can actually survive in a team bat if the enemy team focuses him. All he needs to do is spam his Q.
The Bloodthirster is a backup. He needs some AD and basic vamp for that short CD + some damage for the turrets.
All else, he'll have good Defense, AP, Vamps, HP, Penetrations. A solid warrior.
Wicked Sick.

Good Luck in Game.