Renekton is a really strong champion with a lot of base damage that is a real nuisance to lane against. Although he doesn't scale well for lategame, he can still be really good; my guide will teach you how.

I like to take more offensive rune and mastery pages since you're aiming at winning the early game and leaving your items to help you scale more easily into the lategame, if you win your lane, which with this build is very probable unless you have an off day, you shouldn't have a problem with your lategame. I take 21/9/0 masteries to help win that early game, most tank guides would suggest to use 9/21/0, but you're playing Renekton who aims at winning the early game and bullying people out of lane. the 4 points in sorcery are to help Renekton escape ganks since he isn't the most mobile champion in the world and allows him to spam his level 5 Q in teamfights. 4 points into deadliness allows for a bit more damage at level 18 and opens up the tree to more important masteries. 3 points in Havoc, 2 in Brute Force and 1 in Executioner to force those early trade wins. 1 point in Weapon Expertise and 3 in Sunder to make more use of your combo in teamfights and help keep sustained during them. Finally, 2 points in Butcher and 1 point in Destruction to help ensure you win your lane and push a little faster allowing for a stronger split push.

Your rune page is designed so that you win your early trades and scale your resistances nicely into mid and late game.

Because Renekton isn't incredibly mobile since he only really gets a nice dash if he hits something with Slice, Flash is preferred. Helping him escape ganks easily and lock down back line targets with your W. Ignite serves 2 purposes; It helps win those crucial early trades and also shuts down the opponent's AD carry's life steal or any other regen based champion the opposing team may have.

Cull the Meek is your most useful ability as it allows you to hit everyone for good damage in a teamfight and helps you sustain through it. By taking a second point in it at level 3 it helps you to farm and bully the enemy out of lane. Your second most important skill is Slice and Dice: By using it to enter a teamfight you shred people's armor with it, giving your team an advantage. It's also your only escape tool so the cooldown drop by putting points in it is much appreciated.

You want to try and always hit something with the Slice part of your E, as only Dice shreds armor. Try to hit as many targets as you can with your Q, it gives massive amounts of life steal and will help you sustain in team fights. Always bear in mind that your Q has a longer attack range than your auto attack. Try to hit carries with your W, prime targets would be champions such as Master Yi, Fiora or any AD carry. Try to activate your ultimate after you've dived to ensure that your enemies take as much damage from it as possible since it really hurts a lot as well as gives you a large chunk of free health. Always remember that you're manaless, so feel free to spam your abilities on the minion wave and push faster.

Like any other champion, you can't pick Renekton just because you feel like it, you pick according to your team. Renekton likes a heavy damage dealing Jungler like Aatrox, Master Yi or Elise. You may be attempting to win your early game, but this doesn't allow you much kill potential since you're not building much damage so a lot of damage in the jungle is very nice. In ranked play, Renekton does really well against carry top lanes like Jayce. And completely counters a team that includes Jarvan IV since if he lands his ult on you with any of their team mates caught in it, they're going to take heavy persistent damage. Team comps with good single target damage are favored for Renekton instead of area damage.

Rejuvenation bead + 5 + ward start is good against champions like Jayce, Elise, Kennen or any other heavy poke top lane. Can also be good to out sustain very tanky top laners like Malphite. Long Sword + 2 start is a nice alternative due to Renekton's mad base damage and life steal on his Q allowing him to out-trade other offtanks early with a Long Sword and helping him with his farm. First back you want to try your best to back with enough to get a Giant's belt and Boots of Speed because an early Giant's Belt on Renekton is really scary, since you already have either a lot of sustain or damage, they will have to rethink what they're doing. Grab another Long Sword if you don't already have one, you should have enough because you can stay out and farm for longer because of the amount of sustain you started with. If you already have on, grab a ward or two and maybe some Health potions. You want to almost rush a Sunfire Cape. It stacks damage with your ult and gives useful armor and health. The negatron cloak can be switched for cloth armor or warden's mail. Depending on your match up. We add another Long sword to build the other you may have picked up into a Brutalizer. Next you want to take a Spectre's Cowl to get some nice sustain and Magic Resist that you can build into Spirit Visage which increases your Q's lifesteal by 20% helping you sustain in teamfights. Mercury treads are favored for the Tenacity passive, the amount of armor Ninja Tabi give is tiny, too. Brutalizer builds into The Black Cleaver which provides a nice amount of damage for you and gives good utility in teamfights by shredding armor. Warmog's shouldn't need to be explained, a classic tank pickup that provides large amounts of health and sustain. You don't need your Black Cleaver until you're fully teamfighting so leave it until lategame. If nobody picked up a Locket of the Iron Solari by now, you should. Otherwise, grab a Randuin's Omen. Randuin's can substitute Locket of the Iron Solari or Spirit Visage if you don't need the Magic Resist or someone else already has a Locket. Ravenous Hydra can be really scary to play against on Renekton. It adds to the life steal on his Q and makes him hurt MUCH more. (Only buy when fed)

Renekton is a really strong early game lane bully, the reason he builds tank is because his late game is really bad. If you don't do well early you'll be nearly useless later on. He's really strong against carry top lanes, like Aatrox, Master Yi, Fiora, Jayce and Pantheon. He loses out to tankier champs such as Shen, Dr. Mundo, Nasus, Malphite and Olaf. Positioning is key with Renekton, if you don't get it right, you'll end up doing nothing in a teamfight. You want to be up in everyone's face getting as much passive damage off as you can and focusing down the AD carry. If your focus isn't on point, you'll be pretty screwed. A top laner + mid laner can kill you easily.