Edit 1/25/12- After playing the build a little further, it came to my attention that it wasn't as all-purpose as it could be. Edited to make it more well-rounded.

*Note- This build assumes you are at least decently familiar with LoL. If you are not, I'd look up some tutorials before reading. Also, I will not be covering Renekton's abilities, as there is the LoL wiki for that. So if you're not familiar with Renekton's abilities, look those up before reading this too.*

Welcome to my build for Renekton (and first guide of MOBAFire). Crit-nekton: The Efficient Butcher. This build for Renekton focuses on making him as beefy as possible without sacrificing damage output, as a full dps Renekton can be killed quite easily, and a full tank Renekton isn't playing to his strengths.

This is a Renekton that can stand up to punishment, and come back for more quickly. Though it is good to play this build defensively during laning phase, as this is a Renekton who is not very fast, but can leap in for a quick kill if an opportunity is given.

A video showing the damage output and survivability in action... Play Video Without further ado... let's get started :)

Pros:
Can spam abilities early game, making for great early damage output
Great survivability in lane
Great survivability late game
Great early and late game damage output
Great 1v1 fighter
Ult is great in both 1v1 and teamfights

Cons:
Slow... easily outrun (though slice and dice and taking ghost alleviates this somewhat)
Very vulnerable to crowd control (especially silences)
Very vulnerable to nukes/burst damage early game
Easily ganked if alone
Non-furious abilities can lack damage early game (before grabbing atma's)
Can suffer from KSing if with a greedy partner

I start with greater marks of desolation, as this increases his early-game damage and will most likely cause you to do true damage to all characters except tanks. Also helps Renekton's late-game. Not much else to say otherwise.

Renekton does not have very good base armor, so any seal with armor increase is very beneficial. I go with greater seals of resilience, but greater seals of defense can be a viable option too; though it'll effect Renekton's early game, where he excels.

On the flipside, Renekton has extremely good starting magic resist. So take flat magic resist glyphs and make this resistance even better.

Finally I go with Greater Quintessences of Desolation for early armor pen. Again, focusing for max damage early game is one of Renekton's biggest strengths, and these definitely help with that. Also, again, come in handy late-game as well.

For a beefy Renekton, I recommend a 9/21/0 build. In the offence tree, I take the offense summoner spell mastery, as exhaust and ghost work extremely well for Renekton. Then I take the +3 in damage output, as it meshes well with his rune setup. Then I take the 4% attack speed boost, as Renekton's attack speed is fairly slow, and anything to speed it up a little helps. Finally, I drop a final point in the 10% aarmor pen, as it will help Renekton's late game, which falls off a little.

For the Defensive tree I take the armor and magic resist catagories first, then put points into all the health masteries in the defensive tree. This works to make Renekton beefy early game, as well as later game; as the bonus to starting health will help him early game, and the health bonus over time will keep him beefy as the game goes on. The extra health regen will also put him on par with most other champs starting health regen, as Renekton's base health regen is low. Next, I take the defensive cooldown mastery, as any Renekton makes cooldowns a priority, and then I finally take the final two masteries involving durability for sustainability in lane.

As with most melee champions, speed early is your friend. So starting with boots and three health potions is your best option. I've seen doran's blade as a fair starting option, but I wouldn't go for it, unless you're soloing a lane.

For your upgraded boots, go for Ionian boots, unless they have a carry getting fed. As with any Renekton, cooldowns are your first priority, as they allow you to spam your abilities and put out damage very quickly. My next buy is a brutalizer because again 10% cooldown is extremely helpful, plus the extra damage and armor pen are helpful too. Now your cooldown reduction will be brought to 25% at this point.

Now that the cooldowns are out of the way, time to bring up renekton's attack power big time, and pretty much the core of this build, Atma's impaler. Most builds have his for Renekton late game, but I've found taking it early is still quite beneficial, because at around lvl 8-10, when you'll be picking this item up roughly, he still gets an attack increase about equal to a BF Sword. Plus it's got armor and an 18% crit chance, and anything that can give you a 300+ crit early game is a huge advantage, so rush atma's as early as you can.

After this we gotta give Renekton more sustain, so I pick up Force-of-Nature for the speed and great health regen. Then we power up atma's massively by getting warmog's, not only does it give more health, but gives even more to the already high health regen of FoN.

If you're experiencing an extremely long game, I recommend upgrading brutalizer to ghostblade. As this will increase your crit chance with atma's and give you slightly more armor pen.

The last item is up to you, but I often pick up Black Cleaver for the extra late-game damage and armor debuff ablities.

If the enemy team has any AD carries getting fed, a thornmail can be helpful.

Merc Treads are a great buy for Renekton if the enemy has a high amount of crowd control.

Frozen mallet is also a good buy to get more out of atma's if you're dealing with a speedy team.

An Infinity edge can be used as a late game pickup to get more out of your crit from ghostblade and atma's, but this is extremely situational, and should not be grabbed often.

A guardian angel is an amazing pick if you get fed early, and take the slot of you FoN if you pick one up.

On the flipside, a sunfire cape is a good grab for a renekton who has fallen behind, as the passive synergizes with your ult well, and increases your farming potential big time.

Last whisper is also effective at busting through enemies that are stacking armor, so this can be a great late game pick-up too.

I choose ghost and exhaust for summoner spells. I used to do flash, but since flash has been nerfed and slice and dice travels the same distance (sometimes more), I just use ghost as my extra escape mechanism.

Exhaust I use as an anti-enemy escape mechanism (because of the slow), or a tank buster, as the lowered armor and magic resist on the enemy lets me do even more damage.

If you are looking for a champ that's made for getting lots of kills quickly, Renekton is probably not a good choice for you. He will get a fair amount of kills going in a good game, but he's no carry. His best asset relies on outlasting his opponents and finishing them off when they try to make their getaway.

Remember this is also just my recommendation for a build, there are a few other very viable builds out there, and I did use many of those before creating this custom one.

Thanks for reading, and I hope you enjoy the croc! :)