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.
My name is ThePoonisher and i have been playing league for the best part of 2 years now. From those 2 years i have mostly played jungle and so i have kept myself up-to-date on what is "op" and can win games. From this, i have found that master yi is actually very strong in the jungle at the moment. With games being quite short, master yi is the perfect champion to carry on in the cuurent meta. He can be very effective early game and can completely shut down a lane from the get go. Many people don't like to play master yi because they think he is easy to play and boring, however, there is some room for outplay and it is harder than it looks to play him well.
Honestly, it doesn't really matter what you build on yi past devourer, but there are items that can make it more effective and easier to farm up to that all important sated devourer. My favourite item to build on yi is dead man's plate. It really compliments the idea of yi just charging in and attacking the back line. Building it first or second item can be really efficient as it makes you very tanky and still allows you to do a lot of damage. Botrk is still a very good item for yi even if you only use it for the slow. It can really help you sustain and to do a lot of damage when combined with devourer. I tend to get botrk second or third item depending on the enemy team's composition.
On yi your primary early game focus is to get to devourer, and sated devourer as soon as possible. This means going for early kills as well as possibly counter jungling to get more gold and devourer stacks. I find it very useful to get first blood, and as yi you can always get an early kill in top or mid because you will be on near full health through use of the life steal on hunter's machete and using the w. don't be afraid of flashing for a kill as it can literally win you the game. Once you have sated devourer you become one of the strongest 1v1 champions in the game so never be afraid to just press r and kill the out of position adc. You can also tell your team to group because yi is very effective in a team fight. If your team is behind try going for solo kills and split pushing, because this can help you to win the game. Split pushing can be effective as you push rather quickly and are very mobile with dead man's plate to get back to your team. Late game with a full build you are virtually un-killable so just go for fights and try to attack the carries. Your ultimate makes it very easy to stay alive and avoid slows. You can also melt tanks with blade of the ruined king. This also means you can also melt dragon and baron, so don't be afraid to make a dragon call if the enemy team is not around.
YI CAN BE OP if he is played right so give him a try. I have carried some games, and also turned games around where it seems impossible to win. Yi can be good against tanks as he avoids slows and can also melt tanks with his use of blade of the ruined king. Good luck summoners!