it may look like he has health problems but he doesnt due to his crazy ability once he engages someone he gains back his life faster than most others.

he is a full jungler/minion wipeout once he gets the latern. by level 9 or 10 he should be able to one v one the dragon easy. he engages multiple enemies after they've been engaged by his partners

his biggest con is if he fights against a teemo due to the blinding effect. heimer not bad due to having to guess where yi is going. yi is a good chaser due to his abilities and has no problem pushing late game. this build can win ive won a 2v3 with this build because i killed the entire team multiple times they all had 3k and i had 12k because of this build i was 18-0-3 and i did this in 20 minutes i've never made a team that mad at me before so my point being this build really works.
his pros are he can solo top he can out level the entire enemy team if not kept in check. he can out gain money wise most other champions. slows cant effect him with in his final which makes him hard to stop. his transdimensional slash can aviod all area of effect and karthus's final due to while your doing it you cant take damage and become untargetable.
there is one more con but life steal basically negates it but its thornmail due to it negatine some of your life steal its basically saying you better kill them before you kill your self.

Abilities

Double Strike
Master Yi strikes twice every 7th attack.

-Great Passive, it can be used for tower killing to dealing massive burst damage at low levels. Your FirstBlood tool.

Alpha Strike
Master Yi leaps across the battlefield striking up to 4 enemies, dealing magic damage to each enemy with a good chance to deal 400 bonus magic damage to minions.

Meditate
Master Yi channels, restoring health over 5 seconds. While channeling, Master Yi gains armor and magic resistance.

-This is an awesome skill which is often overlooked. It has many uses since it adds enormous amounts of armor + magic resist.

Penta-Kill foiled
Wuju Style
Passive: Increases physical damage. (Active): Master Yi can activate this ability to double its effectiveness for 10 seconds, but this removes the passive bonus until Wuju Style becomes available again.
-Default/Passive attack damage

Highlander
For several seconds, increases Master Yi's speed of movement and attack by a large percentage, plus makes him immune to all slowing effects. Additionally, killing a champion refreshes all of Master Yi's cooldowns, and scoring an assist reduce the cooldowns by half.

yi sometime has problems with tanks due to the fact of the nerf to life steal a month or two ago so thats the reason i recomend the armor pentatration rune and the defense and magic resist one are for early game when your trying to aviod dieing.

the masteries i chose help out yi in every part of his fighting from lifesteal to armor pentatraion, attackspeed, critical damage, and normal attack damage early on. armor and magic resist masteries are early game and will keep minions and other champions from doing as much damage. these will help you stay in battle in the early parts of the game for very long periods of time.

the sommoner spells i choose are flash and ghost they are multi purpose they can be used to chase down people get away from tower or they can be used to get out of gank. they can be used to get kills or get away from being killed.

once you get to the bloodthirster you should be able to stay in the battle a very long long time. you will be gaining health so much that when you get badly injured you can walk over to a minion and say hey i just gained back 100-200 health a strike.

all rights of yi's storyline goes to the LEAGUE OF LEGENDS website.

Keeper of the ancient art of Wuju, Master Yi is a mystical warrior from the isle of Ionia. He descended from one of the few tribes dedicated to the preservation of Wuju, a martial art founded with the principles of absolute spiritual awareness of one's self and one's enemy. When the armies of Noxus invaded Ionia, Master Yi joined in the Ionian defense to fight the craven enemy, bringing his village honor through his unparalleled mastery of the blade. The ensuing battles ravaged the land, but no conflict inflicted as much horror as the day the armies of Noxus closed in on Yi's village. Left undefended, the village became the unfortunate test subject of the latest invention by an up-and-coming chemist, now known as Singed. The remains of the village that Master Yi returned to were so horrific that it remains a festering scar on Ionian history. To this day, no Ionian will ever publicly speak of what occurred.
After the Noxian invasion was contained, Master Yi fell into a deep isolation. For years, he trained morning to night, speaking to no one and refusing offers of consolation by fellow Ionians. The only thing stopping him from madly charging into Noxus battle lines headfirst was his pledge to keep the Wuju style alive. Even though he seethed with impatience, his rage became a tool for sharpening his practice of Wuju, developing stronger and deadlier skills for his eventual vengeance. The only thing that roused him was news of the League's formation, and Noxus's subsequent enrollment in the League. Master Yi now brings his mastery of the blade to the League of Legends with unflinching purpose: to avenge his kinfolk and end the predations of the Noxus once and for all.

"The art of Wuju lives on in Master Yi, and is plunged through the hearts of his foes."
Soraka, The Starchild
Goggles from the InventorEdit
The goggles Master Yi wears are a techmaturgical device that was gifted to the champion by Piltover's own Heimerdinger, the Revered Inventor. Master Yi first used these goggles when defending his homeland from Noxus invaders in the time after the League has just formed and before Ionia had affiliated itself with the League. The goggles are fitted specifically for Master Yi; while someone else may wear them, they won't receive anywhere near the same benefit as he does himself.
The one-of-a-kind goggles, known as the "Seven Lenses of Insight", allow Master Yi to see across a wider range of the spectrum than normal people see. They also give him abilities not dissimilar to that of real world binoculars and telescopes. The goggles are synced to Yi's own magical resonance, allowing him to adjust settings without the use of his hands. He simply thinks what he needs, and the goggles act accordingly.[1]