This Warwick I built does little AD and massive Magic damage, the magic pen from runes and malady will cause any squishy and most Tanky dps to crumble before you. 1500 to 0 in 2 seconds it may seem like your not doing much damage but with madreds, malady, and wits end you'll be dominating with your 2.5 attack speed and 350ish dmg per hit. (side note) if fighting a ranged character go blood scent heavy instead of hunters call it will allow you to catch them if you hurt them enough.)

The runes are merely to aid in harassing your opponent and sweeping up as many minions as possible. but these runes also give you a considerable advantage against your opponent at level 1 if he/ or she is cocky enough to go toe-to-toe with you; well placed ignite and exhaust will end up in a definite kill.

Now Malady's MD is 20, and wit's end MD is 42 to top it off 4% of the opponent's health in MD from Madreds (Example, 4% of 3000 is 120), so a total of 182 MD plus 172 AD per hit so around 354dmg per hit, of course it is reduced by defense but it still damages your opponent by a significant amount, but your dmg doesn't dwindle, the damage bonus from your base increases infinite duress's magic damage, BUT every on hit MD item you have stacks with that damage so around 600dmg duress because of the spells damage plus the on hit MD 182 times 4 = 728 so around 1328 dmg. after duress is complete.

Pros:
Powerful late game.
Life steal keeps you in lane, and alive in a fight.
Pops Squishies in seconds.
once you have your items you can possible change the game.
Cons:
Very team dependent early game.
If disabled while duressing a lot of your damage dealing is cut.
Can't really damage towers/buildings.

If your lane is pushed too far (assuming this is a 3v3) farm jungle creeps till the lane balances/ or gank other opponents. Of course this is common knowledge to most but it can't hurt to explain. Also try to deny buffs as much as possible.

This Warwick as a team player is suppose to destroy the team's most damaging player as fast as possible, going down the list as he demolishes them, but if the situation calls for it he can save his infinite duress for characters like nunu or katarina to shut down, their ultimates for a successful team fight. (If you have a awesome teammate that places wards, you will literally pick off their teammates like a predator in misty jungle.)

Well I hope this helps anyone, I'm open to CONSTRUCTIVE criticism I know this build isn't explained well enough but I tried, I hope this helps you guys dominate!