Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This is a test build ive been useing for Twitch.
The logic behind it is that yes twitch has fast attack speed and his poisons do alot of damage, but his Expunge is where the damage is at.
The way it works is like this. Expunge does a base 150 damage at rank 5, then it adds your AP to the mix (which is 330), and then for each stack on them, adds and additional 60 damage, which at 6 stacks (the max) is 360 damage. so all together your hitting the target for 840 points of damage in under 3 seconds. and this can be done every 8 seconds. Now imagine you popped Spray and Pray before you came out of stealth. You are now doing 1680 damage in 10 seconds to everything thats there (with a proper set up) and thats not counting the 120-150 damage per arrow hit.
Add this all up and we get this: 1740 damage to a single target with 1 application of a 6 stack'd Expung or to a group with Spray and Pray, and if you get off 2 Expunges quickly, thats 3480 damage to a group in 10 seconds.
My item choice is pretty simple, i snagged attack speed and damage and ability point stuff to get the most optimum use out of Twitch's unique Magic/Physical attack method.
So just stay hidden, set up your spray and prays properly, and dont be afraid to take a few minion hits if it means more stacks of expunge to get that Killing Blow.
This all is of course still in testing, but any and all comments are appreciated for im sure some old Vets of Twitch might have some trade secrets i dont know about.