This is my first build so don't hate me, now I personally love Renekton but sadly his general build concept just got screwed up in a recent patch so I have decided to introduce a newer concept on him. You need to do too much damage to be ignored but at the same time mitigate enough to survive being focused. My build may seem strange but I have gotten 2v5 pentakills with it and won 1v3 fights with no assistance. Think of Renekton as Charlie Sheen, gota have that tigers blood. (I wont go into much detail but I'l explain the basic concept of my build, runes are open to interpretation. Thats a general draft of the runes, I'm still not sure if i should exchange the dodge for armor but so far dodge is working out for me.)
Pros / Cons
-beast off tank
-pain in the *** to kill if you can initiate right
-good synergy with most champs
-have to build up some momentum before you can begin face-rolling fools
-Is fairly susceptible to stuns or suppresses while team diving
-relies on massive life steal to tank
Skill Concepts (The Method to My Madness)
Starting with stun is important to handle anybody who tries to harass you or that gets stupid pre-minion spawn. First to be maxed should be your AoE to help farm and mitigate harass, this goes contrary to starting with stun but trust me it does work. Slice & Dice is a good skill with good damage but you wont need it too much early on so I just use one point so that I can manipulate it as a chasing skill, you can switch points up at any time depending on how you like to play him or what you need when though.
Will elaborate on items later but all you really need to know is that with this build you will be doing massive damage while at the same time be rounded with your defense, after you have the Hex Drinker (Hex Drinker can be switched with thornmail if needed) you can start team diving in fights. The way to really look at this build is to look at Renekton as a pseudo Anti-Cary. You have not only the damage but also the survivability to dive a team to take out a cary and then get out. Quick note on the boots, those are game dependent. Remember no guide is set in stone, you sometimes have to tweak it to beat the team you're against. Also ghost blade can be switched with a Randuins Omen if you need more survivability.
One thing with ghost/flash. This is open to player preference, I prefer mobility so i get ghost but it can be switched with flash if you like. (Flash is much more effective to get out of the fray after you dive a team for their cary.)
I'l elaborate the build soon, I still need to test and tweak myself but the pst few games I used this build and walked out 24-9 while most of my team mates were 8-10 or 1-3, and the opposing team was just about as fed as i was. Though I'd love to get that 9 down to a 4 or 5 at max. Comment, leave critiques, vote, let me know how to make this better. Thanks for reading.