Hi and welcome to my Feral Flare Master Yi guide for jungle.
With the new update a new item did arrived, and it's the Feral Flare, which is a must for attack speed based junglers like Master Yi, Xin Zhao, Udyr and Warwick .
Master Yi was and is my favourite champion since i started playing League, he is fun to play and VERY EASY, and if you get fed you can destroy the enemy carries, 2-3 shotting them late, or when you have full build.
If you play this game for fun or you like assassins which can destroy the carries and escape 'no-problem' i think you may like Yi.
We'll talk about everything you must know to rule on Summoner's Rift with Master Yi.

There are LOST of items which work with Yi, but i realised a nice build, which gives you no sustain but gives you the ability to 2 SHOT an enemy carry or support ( if squishy ).
If you want lost of sustain you can try to replace some items from BUILD 1 with Bloodthirster or Ravenous Hydra.
If you want to solo baron at minute 20 grab a Spirit Stone besides Feral Flare, which will give you more damage against neutrals, being very helpful, just be careful, ward the enemy bushes to see if they come, and try to dodge the baron knock-ups, them can ruin your plan.

I suggest you to go Flash& Smite but you can also go Teleport& Smite to apply map pressur or to backdoor.
Ghost is also viable, making you fast like Sonic, comboing it with Highlander and Youmuu's Ghostblade.
Take Smite EVERYTIME YOU JUNGLE, tough you can take the camps even without Smite, Smite is very important at controling buffs like baron, dragon.

In the last patch, which contains Feral Flare, Master Yi has been banned much more recently, but if you got the occasion and you know how to play him he is a must, if he gets fed early he can carry all game, until the enemies make a crazy comeback.
I don't suggest you to go Master Yi against an Jax, or an Aatrox, they can STOMP you in every stage of the game, but again, you can pick Master Yi if you're confident you can win/you got a good engage team which can protect you and these counters can't delete you.

Pros

+ Fast clearing speed + Amazing damage mid/late game + Amazing ultimate + Can tank pretty well with his Meditate

Master Yi is an assassin with very fast clearing times which make your feral flare easy to stack and great mobility with his Highlander which make him un-escapable from a gank.

Pros

- Very squishy - If falls hard early, he's useless - No CC

Yi, like every assassin, is very squishy , he also doesn't have CC and if he falls hard early he is nearly useless for the rest of the game, until he just farms up and kinda realises a build..

Let your teammates engage first then just pop your Highlander and spam your Alpha Strike, this is the best thing you can do in teamfights, otherwise, you will get focused, cc-ed to hell, and killed, which is NOT GOOD.

Start at the blue, make the wolves, then go to your red. After you just need to clear the camps until your blue/red respawns.
Jungling with Yi is very easy, he has an extremely fast clear time and he is a beast at ganking after level 6.
When you gank just pop your Highlander and go all in, with/without the help of your teammates.
There are not much people that can escape your ganks, but here are some of them : Caitlyn Jax Tryndamere Tristana.
Be careful, your Alpha Strike will follow targets, and if they flash or use leaps/dashes/etc you will follow them if the Alpha Strike is timed correctly, this can put you in a difficult position, forcing you to dive or flee, or can put you in an excellent position, which can mean an easy kill.
Try to get as much kills as you can, but sometimes you may let some kills to top laner, mid laner, adc or support .

Your big counters are Jax Malphite Tryndamere and your easy matchups are Hecarim Nunu & Willump Evelynn.
Of course these counters/matchups do not matter every time but in the most of the cases it goes like that.

So, yeah this was my guide on Master Yi, it was a short but was 'straight to subject one', hope you enjoyed it and it bringed you some wins on solo-queue or every type of match.