nice and solid guide dude ;)
Choice of items is very good and the description also helps those who don't know Renek vry good.
Well done!

Grtz,
Just a Reflex

@Starfeash
1. Even against someone with lower health, lets say 1500, Madreds will proc for over 50 damage on each hit. That means you boost the damage of your W by 100-150 (not to mention the AD on Madreds boosts it anyway). You buy Madreds for the burst it adds to W, not for the extra damage on your auto-attacks.
2. It diversifies your damage by dealing magic instead of physical, which is good.
3. Its very rare to play games, even in solo queue, where there isn't at least one enemy with high health. Being able to take down any target makes you much more dangerous and much harder to counter.

If he is not an auto attacker then why the bloodrazor? Also, you might look like a **** if they have a team with no high health champs. I mean, they will die, but it might make you feel bad for wasting a bunch of gold.