Master Yi Build
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.
Master Yi build against a heavy caster team.
I use 0/21/9 masteries with improved cleanse and ghost.
Start with Meki Pendant and build it into Tear of the Goddess.
Your nexit item is Mercury's Treads.
Now you can build your TotG into Manamune or buy Hexdrinker before.
Buy Wit's End for attack speed and magic resistance.
You should buy Frozen Mallet to get some health.
Your last item is your choise. You can Guinsoo's Rageblade or Infinity Edge or The Bloodthirster.