Master Yi is my favourite champiom because he kills the enemies very fast and then can run from him because he can use Highlander and Alpha Strike. He becomes strong since the beginning because Wuju Style's level 1 passive ability gives he 15 attack damage.

It's important to have a good attack damage and some life steal in the beginning, so start the game with one Doran's Blade. Then, your boot will be good if gives you some atack speed because Master Yi needs it and Beserker's Greaves gives it to Yi. Bloodthister is the item that gives you a good life steal and attacking very fast like Yi you recover life fast with some life steal. Now the most important item for this champion, the Phanton Dancer gives you attack speed, important to Yi; movement speed, important to Yi to and some critical chance.When you buy the Black Cleaver you will be feeded because you attack damage and speed will be high and you'll kill anyone. If you want more attack damage you have to buy one Infinity Edge but if you are dying fast you can use another Bloodthister to have more life steal. Guinsoo's Rageblade is good because you'll improve your ability power, attack damage and attack speed.

With this build you'll kill any enemy in a few seconds. Good luck in your game and remember, always use Highlander to kill one enemy because you recover it if you kill with this ability activated. Good game!