Twitch

Bottom

Rat-Ta-Tat

Massive sustain and lane trade damage.

Precision

Improved attacks and sustained damage

Press the Attack

Attacking a champion 3 times will expose them, dealing bonus damage and causing them to take more damage from all sources for 6 seconds.
Triumph

Takedowns restore health and grant bonus gold.
Legend: Alacrity

Takedowns on enemies grant permanent Attack Speed.
Coup De Grace

Deal 7% more damage to low health champions. Gain AD/AP after kills or assists.

Sorcery

9% attack speed, 10 ability power or 6 attack damage

Celerity

Gain 3% extra MS. Gain extra AP or AD, based on your bonus MS, Adaptive.
Gathering Storm

Gain increasing amounts of AD or AP, Adaptive over the course of the game.

WhyPress the Attack

Press the Attack massively ramps your damage, especially when looking to come out of [Q] stealth and assassinate a target. The extra burst and amp will make your [E] hit like a truck.

WhyTriumph

Triumph acts as a largely mid-fight heal for late game teamfights where you are able to hit the majority of the enemy team with [R].

WhyLegend: Alacrity

Twitch is an AD Carry that naturally relies on getting as many auto attacks in as possible for extra damage. Alacrity will also help you build passive stacks faster in the early game for [E] burst damage.

WhyCoup De Grace

Coup De Grace is the go-to rune for reliable bonus damage. Paired with the burst of [E], Twitch's damage can scale incredibly well with a small lead.

If you're playing into a number of tanks (Jungle, Top, Support) Cut Down can be a great alternative thanks to your ability to hit multiple target in a teamfight with [R].

WhyCelerity

Celerity is a naturally strong rune on most Crit AD Carries as the bonus Movement Speed synergizes well with your Zeal items.

WhyGathering Storm

Gathering Storm is your late-game insurance policy. In a 40min+ game you will be bale to potentially take over a teamfight with a well positioned [R].