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 build a made up from my own knowledge of twitch ownage... Enjoy.
1. Buy a longsword and start of with Expunge.
2. After several minion kills and a first blood head back to base and get your Sword of The Occult.
3. After you have your sword buy a dagger first then pick up your Berzerker Greaves.
4. By now you should have around 2-5 kills maybe 6 if your good. By now you should be able to buy a Vampiric Scepter to start off your Malady.
5. Depending on how much money you have you can either get a Recurve Bow or a Dagger for your sword of the Divine.
6. To start off Infinity Edge I usually save up for a B.F. Sword (depending on how much money you have and how the game is going). Then I usually buy a Pickaxe next and finish it off with a Cloak of Agility.
7. And to finish off Phantom Dancer and the last seconds of the game I get a Zeal (obviously) and buy Phantom Dancer.
If you build my build correctly and the game has gone in your favour then you should be ownage.