This is my Yasuo guide - Yasuo is a melee champion with some very interesting mechanics. He is an assassin/fighter and his skillset can be quite devastating against ranged/casters. Yasuo is quite suited to the Mid Lane but can be played Top Lane and Jungle, although Mid Lane is where he really shines.

Overall, Yasuo is a very high skill cap champ, with lots of tricks and things to keep an eye on. His damage is insane when you are able to play him correctly but he can be very frustrating when mess up. Hang in there, practise hard and trust in your blade!

Hopefully this ULTIMATE guide will help you get the most him :-)

Official Lore
Yasuo is a man of resolve, an agile swordsman who wields the wind itself to cut down his foes. But this once proud warrior has been disgraced by a false accusation and forced into a desperate fight for survival. With the world turned against him, he will do everything in his power to bring the guilty to justice and restore his honor.

Once a brilliant pupil at a renowned Ionian sword school, Yasuo was the only student in a generation to master the legendary wind technique. Many believed he was destined to become a great hero. However, his fate was changed forever when Noxus invaded. Yasuo was charged with guarding an Ionian Elder, but, foolishly believing his blade alone could make the difference, left his post to join the fray. By the time he returned, the Elder had been slain.

Disgraced, Yasuo willingly turned himself in, prepared to pay for his failure with his life. He was shocked, however, to find himself accused not just of dereliction, but of the murder itself. Though confused and racked with guilt, he knew the assassin would go unpunished if he did not act. Yasuo raised his sword against the school and fought his way free, knowing his treason would turn all of Ionia against him. Now truly alone for the first time in his life, he set out to find the Elder's real killer.

Yasuo spent the next several years wandering the land, seeking any clue that might lead him to the murderer. All the while, he was relentlessly hunted by his former allies, continually forced to fight or die. His mission drove him ever forward, until he was tracked down by the one foe he dreaded most – his own brother, Yone.

Bound by a common code of honor, the two warriors bowed and drew their swords. Silently they circled one another under the moonlight. When they finally charged forward, Yone was no match for Yasuo; with a single flash of steel he cut his brother down. Yasuo dropped his weapon and rushed to Yone's side.

Overcome with emotion, he demanded to know how his own kin could think him guilty. Yone spoke: “The Elder was killed by a wind technique. Who else could it be?” Understanding swept over Yasuo as he suddenly realized why he had been accused. He professed his innocence once more and begged his brother's forgiveness. Tears streamed down Yasuo's face as his brother passed in his arms.

Yasuo Yasuo buried Yone under the rising sun, but could take no time to mourn. Others would be after him before long. His brother's revelation had given Yasuo newfound purpose; he now had the clue that would lead to the true killer. Swearing an oath, he gathered his belongings and, with one last look at Yone's grave, set out with the wind at his back.

The story of a sword is inked in blood.
― Yasuo

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Pros
+ No Mana
+ Great mobility and juking potential with Sweeping Blade
+ Wind Wall can completely shutdown ranged champs and save allies
+ His Ult Last Breath can be chained off other champs Ults
+ In built shield to help in small skirmishes
+ Great damage with items and good play
+ Be 'man of the match' with both killing, juking and saving power
+ Amazing animations, very cool looking champ.

Cons
- Very technical with lots of elements to his kit
- Generally weak early game
- No sustain and squishy - easily focused and shutdown by CC
- His Ult Last Breath can be hard to use
- Steel Tempest has short range and easy to miss.
- Requires farm, items and skill to do damage.

Max Steel Tempest first, Sweeping Blade second Wind Wall last as its more of a utility spell.

Yasuo's passive Way of the Wanderer has two components, Resolve and Intent. His resource bar is Flow and is used to fuel his Resolve.

Resolve

At maximum Flow, the next time Yasuo would take damage from a champion or monster he first converts his Flow into a shield that absorbs damage. After 2 seconds, if not already depleted, Yasuo's loses all his Flow.

Yasuo can have up to 60 / 70 / 80 / 92 / 105 / 120 / 140 / 160 / 185 / 215 / 245 / 280 / 325 / 375 / 430 / 490 / 565 / 650 Flow. Flow does not decay or generate idly. Yasuo generates 1% of his maximum Flow with every ~40 units he travels, requiring a total of 4000 units-traveled to obtain maximum Flow. As Flow generation is based on distance traveled it is also accumulated while dashing, teleporting or when displaced by crowd control effects.

Once the Flow bar is full, upon taking damage from a champion or neutral monster, resolve first produces a shield that reduces the incoming damage by an amount up to the current maximum amount of Flow for up to 2 seconds.
Damage that is negated by Resolve's shield appears as a blue indicator. For example, -60.

Intent

Yasuo's critical strike chance is doubled, but the damage dealt by his critical strikes is reduced by 10%.

The damage reduction applies to the total damage dealt (before damage mitigation). A standard critical strike's 200% damage is reduced to 180%, and a critical strike with Infinity Edge deals 225% damage instead of 250%. The reduction is not a subtraction to his critical strike damage statistic.

o This 10% penalty affects items such as Statikk Shiv. Does not affect damage that can not critically strike, including
o Steel Tempest's base damage and on-hit based damage such as Trinity Force or Wit's End.


RANGE: See below
STATIC COOLDOWN: 5 / 4.75 / 4.5 / 4.25 / 4
PHYSICAL DAMAGE: 20 / 40 / 60 / 80 / 100 (+ 100% AD)

This is Yasuo's main damage ability, it is quite tricky to get used to but learning this skill is crucial, both in landing it and knowing your stack count, consecutive successful casts of Steel Tempest within 10 seconds form a chain. The cooldown and cast time of Steel Tempest is reduced based on Yasuo's bonus attack speed and unaffected by cooldown reduction.

FIRST ACTIVE: Yasuo thrusts his sword forward, damaging all enemies in a 475-unit line. If cast while dashing, the area of effect is changed to a ~375-radius circle.

SECOND ACTIVE: Same as the first active.

THIRD ACTIVE: Yasuo brandishes his sword causing a whirlwind to tear forward, damaging and knocking airborne all enemies in a ~900-unit line. If cast while dashing, the area of effect is changed to an ~375-radius circle. This active resets the chain. Base damage is reduced to 10 / 25 / 40 / 55 / 70 instead.

o The cooldown of Steel Tempest is unaffected by cooldown reduction and is instead reduced by 1% for every 1.72% of his bonus attack speed. This is capped at 66% cooldown reduction with 114% bonus attack speed.

o At max rank, the minimum cooldown is 1.33 seconds (1.4 attack speed).

o Yasuo's 3.5% attack speed per level is factored into Steel Tempest's cooldown reduction and cast time reduction.

o At level 18, Yasuo has a total of 59% bonus attack speed from leveling alone which reduces Steel Tempest's cooldown by 34% (and he requires only 55% attack speed from items, runes and masteries to reach the cap). Steel Tempest's cooldown is effectively reduced by 2.03% per level.

o Steel Tempest critical strikes do not factor in the skill's base damage and is subject to a flat 33% critical damage penalty in addition to Way of Wanderer's 10% multiplicative critical strike reduction. Hence, the formula for Steel Tempest critical strikes total damage is base damage + 150.3% total AD ((200-33)% AD * 0.9).

o With Infinity Edge, the bonus damage is increased to 195.3% total AD ((200+50-33)% AD * 0.9)

o Critically striking with Steel Tempest is calculated on cast, not per enemy hit.

o The third cast will still knock enemies airborne when it strikes as a point-blank area of effect.


RANGE: 400
COOLDOWN: 26 / 24 / 22 / 20 / 18
WALL WIDTH: 300 / 350 / 400 / 450 / 500

PASSIVE: Yasuo generates 4 / 8 / 12 / 16 / 20% of his maximum Flow whenever he uses Sweeping Blade or Last Breath, in addition to the amount that is generated for the distance moved.

ACTIVE: Yasuo creates a wall of wind that slowly drifts forward over the next 3.75 seconds. The wall blocks all enemy projectiles, except tower hits.


This is one of Yasuo's signature moves and is capable of blocking all projectiles (including projectile ults). If you can time this correctly you can block massive damage and easily 'zone' out ranged damage dealers - plus it looks damn cool!

o Sweeping Blade will generate ~7% of Yasuo's maximum flow innately, and Last Breath can generate up to ~18% if the target is at maximum range. This is because Flow-generation is based on distance traveled. The 4-20% gained from Wind Wall stacks additively with the (i.e. in addition to).

o The wall grants sight over a small area and slowly travels forward.

o A projectile is any entity with a velocity that is not classified as a unit (champions, minions, monsters, etc).

o Moving units are not blocked under any circumstance, including dash abilities. Champion-summoned units, such as Orianna's Command: Attack and Maokai's Sapling Toss, are not considered to be units until they hit the ground - and thus will interact with Wind Wall while en route.

Here is a video by Kimimoto going over what Wind Wall can block.