Renekton is a tanky, melee, manaless champion who is extremely versatile in terms of item build and masteries. He is able to solo lanes with ease and dominate mid and late games and is able to hold his own against almost anyone. With this build, you will be almost unkillable with near 3k hp and 200 armour and 100 magic resistance. To top that off, 300 damage on someone that tanky is nothing to scoff at.

Runes are pretty straight forward on Renekton. All his abilities, bar his ultimate, are physical which means armour penetration runes are beneficial. They increase his damage output significantly early game, in lane and jungling while punishing squishy champions who don't buy armour in the later stages of the game.