So that's my "Renekton"-Guide!
Its quite tanky and I really like to play it.
So if you got rid of AD Renekton, this is your choice.

I took the RED-Armor Penetration, cause its always good having a nice dmg-dealer with armor penetration so you arent just tanky, you are tank killer too.
Anyway it's a nice rune for top lane because top lane is most tanky.

I also took the YELLOW-Armor, because you really need some armor so you can engage a fight against carry really soon.

Then I took the BLUE-Magic Resist, because it's like the armor a really ncie rune to have.
Against AP's you are a bit in attitude and you can begin kill them soon.

At last there's the PURPLE-Attack Damage. you need it because you play Renekton on damage.
This guide makes him tnaky but anyway you do a lot of damage.

The Masteries are just simple damage skills and a bit armor,life, etc.

The first item you take is dorans blade. A really ncie start item!
You'll buy it three times for the build.
While you do this you can buy between the time the simple 1-Boots.
After the 3 Doran Blades you get the Ionic Boots, because Renekton is really good if he can use his abilities often and the cooldown reduction is pretty nice for it.

After it you buy an item I really like: The Brutalizer!
It's the perfect AD-start item. You get Nice damage cooldown reduction, that's very important for Renekton.

After the Brutalier you begin building Frozen Mallet and you start with Phage.
The Frozen Mallet is a very nice item for Off-Tanks and Renekton gets his enemies just cause of the slow and the nice damage+life.

Then you take Warmogs or Atmas. It's your decision if you first need more life or instantly want do good damage with Frozen Mallet combo. The Atmas will give you much damage the much life you got. So Warmogs gives you a tanky aspect and a nice damage with Atmas.

After these 2 items you begin upgrading Brutalizer to Youmuus. But you really need to learn when you have to activate the buff from Youmuus. The stats it gives you are like Brutalizer but more and a bit critical chance. It's not really needed but you will need it sometime.

At last you get Hexdrinker and upgrade it to Maw of Malmortius, or instead of it you can buy Last Whisper. The Maw of Malmortius gives you more tanky aspects, but Last Whisper is a nice Damage item cause it gives you another bit of penetration. So if you want to kill tanks, get Last Whisper. If you want be tanky, get Maw of Malmortius.

The Skill Sequence I chose is pretty much focused on 'Q'.
The damage deals a lot of damage and with cooldown reduction and full Fury you kill your enemies fast and in combination with 'W'(Stun) you can handle Top Lane quite easy.
Try start with Slice, Stun him, do a lot of damage with Cull the Meek and Move away from him with Dice, or kill him by moving through him with Dice.

Your ultimate is really nice to get away from enemies or get into team fights.
After a lot of playing Renekton you get a feeling for his ultimate.