This renekton build is fairly simple and awesome for anyone who has played him before.
Please vote up this build, not only because its amazing, but the name is even better :D:D
ReignofAnger
Reign of Anger (Innate): Renekton gains 5 Fury per autoattack. Having sufficient fury empowers Renekton’s abilities with bonus effects, but this drains Fury. When out of combat for 12 seconds, Renekton loses 5 Fury every 2 seconds.

When Renekton is below 50% life he generates 50% more fury.
Ability Description Levelling up
CulltheMeek
Cull the Meek (Active): Renekton swings his blade dealing physical damage to nearby enemies and healing for 7.5% of the damage dealt up to a hard cap. Each target hit grants 5 Fury, up to 25. Heal amount is quadrupled against champions.

When Renekton has 50 or more Fury he deals 50% additional damage and heals for 15% of the damage dealt, the healing hard cap is tripled. Consumes 50 Fury.

* Cooldown: 8 seconds.
* Max Range: 450 (estimate) / 550 in Dominus (estimate)

Physical Damage: 60 / 90 / 120 / 150 / 180 (+0.8 per bonus attack damage)

Healing Hard Cap: 50 / 75 / 100 / 125 / 150
RuthlessPredator
Ruthless Predator (Active): Renekton’s next attack will swing twice dealing physical damage and stunning his target for 0.75 seconds. Each hit applies on-hit effects.

When Renekton has 50 or more Fury his next attack will swing three times dealing physical damage and stunning his target for 1.5 seconds. Consumes 50 Fury.
Physical Damage: 5 / 15 / 25 / 35 / 45 (+0.75 per attack damage) per hit

Cooldown: 13 / 12 / 11 / 10 / 9 seconds
SliceandDice
Slice and Dice Slice: Renekton dashes forward, dealing physical damage to targets along the way. If he hits a target he gains the ability to use Dice for 4 seconds.

Dice: Renekton dashes, dealing physical damage along the way. When Renekton has 50 or more Fury Dice deals 50% additional damage and reduces the armor of targets hit for 4 seconds. Consumes 50 Fury.

* Range: 550 (estimate)

Physical Damage: 45 / 75 / 105 / 135 / 165 (+0.6 per bonus attack damage)

Armor Reduction: 15 / 17.5 / 20 / 22.5 / 25 %

Cooldown: 20 / 18 / 16 / 14 / 12 seconds
Dominus
Dominus (Active): Renekton empowers himself with dark energies, gaining increased size and health for 15 seconds. While empowered, he deals magic damage to nearby enemies and generates 5 Fury per second.

* Cooldown: 120 seconds.
* No Cost

Continuous Magic Damage: 50 / 75 / 100 (+0.1 per ability power)

Health Gain: 300 / 450 / 600