Master Yi Build
Not Updated For Current Season
Now, let me say this first hand before you read my guide. I am not by any means the best player in the game but I would say I fair pretty well.
This build is purely dps and lifesteal and it will burn through people. I have tested it over and over. Now don't get me wrong, this will not make you invincible. You do need to know how to harass and know when to charge your enemies. Working with your team in team fights is also very vital to helping your team push the enemies back and win games. You have to learn to use your terrain and make decisions quickly. If you can't do these things, this guide will not benefit you.
Now onto my guide.
Master Yi is nothing more than a whack-a-mole character. He is also a very squishy one at that. The object is to harass your enemies in the beginning. Take them down little by little with Alpha Strike(Q). It is purely up to you how you play. If you go for an early gank make sure it's not near their turret and make sure it's a 100% positive you will get the kill otherwise it's not worth it. Be careful about being overly aggressive. It can lead to feeding the other team early and leaving your team pissed off at you cause you lost it for them. As I said before. Master Yi is very squishy and dies easily to turrets and spell casters alike in early game. Once you get beyond level 6 he's a whole different story.
Exhaust: This is very important in my opinion. This spell is great for physical champs like Yi and Xin. It's very good for chasing down enemies to stop them from hitting you. It can turn the fight over very quickly for you while keep your health in check or regaining it quickly as you bash them and steal their life back into yours. It's also a great way to slow an enemy and to help you get away when needed. Now I know. Some people say, why don't you use ghost instead. I thought about that but I just don't see the same benefits that Exhaust has especially if you spec into it.
Ignite: This is also a great help for early or late game. Helping you burn down an enemy champs life to also guarantee you get the kill you need or to put a stop in an enemies tracks before they get you instead.
Exhaust + Ignite is very devastating against any champ when Yi is hitting them.
Start off with a Vampiric Scepter. This is vital to keeping your health up. Use it to kill minions and regain health where needed. During this time if you are lucky enough to get an early gank or even built up enough minion kills go get your Berserker Greaves. After that you should be able to get your Malady by level 5 or 6. This is where you start to shine. Malady + B-Greaves + Highlander(R) + Wuju Style(E) will help you get those kills you need or even allow you to help gank where needed.
Don't focus to much on getting ganks. That's where a lot of people make the BIG MISTAKE. They forget about gaining levels and get to cocky and lose ground. You're job is to help protect your teammates, turrets but also to push their turrets. Yi does a lot of damage at this point. During these levels you should be working on getting your Last Whisper. The 40% Armor penetration rips through tanks and especially those squishy casters. The 40% attack speed will also help you knock down opponents as well as turrets faster.
If you are successful in getting ganks and also knocking down turrets you should also be able to gain your Phantom Dancer quickly. If not do not worry. Just creep minions and build up as fast as you can. PD will give you lots of attack speed, movement speed and the physical crit you need to just run through enemy champions and creeps.
At this point you should be working on Yomumu's Ghostblade. The bonus armor penetration and attack speed which is activated manually will help you burn enemies so quick they won't know what hit them.
Now here's the part where you can make your choice as to what to get. I personally go Bloodthirster for the extra life drain. It keeps you alive longer and helps you melt champions regardless if they are tank or not. If you want, you can exchange it for The Black Cleaver for extra armor penetration against tanks but I personally love survivability. At this point you should be carrying if you are playing him correctly and pillaging your way through enemy champs and their base.
Remember, guides are guides. They DO NOT make the player. You have to understand the champions abilities and how to use them to YOUR advantage. It's all in how you play. I hope my guide helped you a little more with how to destroy with him. No character, no mattter how many kills he gets cannot win the game alone. It's all teamwork. Remember that well.