Warwick counted himself amongst the most powerful and revered men in his home city-state of Zaun. Over the course of his infamous career as an alchemist, Warwick won many honors for his craft, not the least of which was a lucrative offer for service in the Noxian military during their campaigns against Ionia. Sequestered in his labs far from the front lines, Warwick and his apprentice Singed toiled relentlessly to manufacture all manner of appalling concoctions for the Noxian army. So potent was his art that even the greatest of Ionia's healers - under the leadership of the Starchild Soraka - struggled to combat the poisons and chemical weapons generated by his despicable mind. Warwick's reign of terror grew so horrific that his very name became a curse in the eyes of his Ionian foes, and they began referring to him only as ''the Deathmaker.''

But even one under the protection of the Noxian High Command is not wholly beyond the reach of retribution. For as Soraka strode across the myriad of death and destruction left in the wake of one of Warwick's chemical attacks, her heart finally gave way. She called down the wrath of the cosmos on Warwick, wishing that his form should mirror the cruelty in his heart - a curse that would come at the price of her aspiring divinity. Within his laboratory, a terrible thirst took hold over Warwick. As his apprentice looked on in horror, Warwick threw open the doors to his bastion and sprinted off toward parts unknown, a bloodcurdling howling marking his passage. He had become a werewolf; a wild, murderous beast. Today, the Blood Hunter fights for Noxus within the League of Legends... thankful of the curse that his now-mortal enemy bestowed upon him.

''The rage of the beast now complements his predatory spirit.'' -- Singed, the Mad Chemist, upon witnessing his master's transformation

This is the BEST Warwick build i hope u guys enjoy =D

Pros
+ Great regeneration skills makes him quite tanky even without lifesteal.
+ Superb ganker. Apears from nowhere with a highly damaging long stun.
+ Best chaser ingame due to passive MS buff when the prey is under 50% life.
+ Extreme survival capabilities for a dps champ thx to huge lifesteal
+ % based damage (Bloodrazor + Hungering Strike) will get even tanks down very fast

Cons
- Costy itemisation
- Stun/blind vurneable
- team dependant

Is a very nice spells for warwick because stop his enemies.

Flash is just the escape mode for warwick because u don't have a ''natural''.

Right for this build offensive masteries
are the best choice, because of course,
you is doing a ATTACK DAMAGE WARWICK =D

Right, this runes gonna give u a strong early game with a huge armor penetration, and a nice armor and magic resist.

Eternal Thirst - Each of Warwick's attacks will heal him for 6 / 12 / 18 health. Each successive attack against the same target will stack this amount of healing to Warwick up to a maximum of 3 stacks per strike. The stacks remain for 4 seconds.

Hungering Strike - Takes a bite out of enemy unit for damage and heals Warwick.
Strikes an enemy for the greater value between 75/125/175/225/275 (+1 per ability power) and 8/11/14/17/20% of the target's maximum health (can only do flat damage to monsters), and heals Warwick for 100% of the damage dealt.

Hunters Call - Warwick lets out a howl, increasing all nearby friendly champions' attack speed for a short time.
Warwick lets out a howl that inspires all nearby allied champions. This increases Warwick's attack speed by 40/50/60/70/80% and all nearby friendly champions' attack speed by half of that for 10 seconds.

Blood Scent - Warwick passively senses weakened enemy champions around him. The scent of blood sends him into a fury causing him to move at incredible speeds.
Warwick senses enemy champions under 50% life within 1500/2300/3100/3900/4700 distance of him; Upon sensing an enemy at low life he will gain 20/25/30/35/40% Movement Speed.

Infinite Duress - Warwick lunges at an enemy Champion, stunning them and dealing damage for a few seconds.
Warwick lunges at an enemy Champion, stunning them for 1.7 seconds. While they are stunned, Warwick quickly strikes the target 5 times for 33% of his attack damage plus 40/60/80. Warwick gains an additional 30% lifesteal while performing Infinite Duress.

Right, now items.

Mercury's Treads: This item give u tenacy,magic resist, and movement speed, what is great.

Madred's Blood razor: THE BEST item that u can get for warwick, with this you kill any tank or off tank or squishy doesn't care you gonna be so strong.

Wit's End: Another perfect item for warwick give a burst on your Madred

Frozen Mallet: With this u gain a huge life, damage and slow

Atma's Impaler: this item with Frozen Mallet, you gonna stay with 250 of attack damage at this point so you gonna be imortal.

Infinity Edge: To complete the build a NICE attack damage item with a nice crit bonus.