I have played master yi much if u try my build out u will own 1 after 1

I have 23/3/4 so i do good dmg and its helpfull ingame

With these item in my build i start early game with boots of speed so i can get FB fast and run away.
And when u got ur Berserker greaves and Zeal u will begin to own abit.
When u got ur
phantom dancer and infinity edge the fun will start u will begin do good dmg and own them.
Soooo now u gonna be the real man with the black cleaver and the bloodthirster no1 can kill u ofc some but u will own them all.
Hextech gunblade will increase ur magic dmg on some of ur spell becouse he can run AP too so some of he's spell will increase dmg.

At FB u need to use ur Wuju style when they are close to the bush that will do hard dmg on them and u get big chance for FB.
At late game i use my Alpha strike, Ultimate, Wuju style = dead

I have taked Ghost so i can get to my enemys if they try to run.
Exhaust is really good use it on ur enemys and u got big chance for kill them.

Pros
+Super to gank.
+Good Chazer.
+Abit good jungler.
+Good to run away if he got low health and hunted.


Cons
-He can die if u get stunned
-squishy (ealy games)
-Low HP

Thats what i had to show you guys. Hope u will get a good game with him with my build GL and have fun.
And remember dear friends try him out before come with bad comments :D!