Heard you like being blind...oh wait. Lee Sin has quickly become one of my favorite champions not only because I can [half] relate, but because he can totally wreck face. Now seeing as this is my first build I'm going to do my best to describe how I play Lee, a physical DPS with some extra survivability. He isn't a huge burst as most people build him and he definitely won't be a main tank, with this build he'll be more of a sustained DPS with, like I said, extra survivability. To all those trolls who downvote...you're not welcome here! :P
But honestly any advice for helping me improve this guide and possible future ones is definitely appreciated.

Greater Mark of Desolation
Lee does mostly physical damage, anything else wouldn't help us out very much for the whole game.

You can't go wrong with extra health, even if it's only 45 extra from seals. Lee doesn't have the most fantastic health early game so a little extra push definitely helps.

Since Lee uses energy, his abilities are mostly reliant on energy regen and cooldown, I chose the latter since it provides a much more noticeable effect.

Any champion in the game can use these, Lee Sin is no exception. Combined with the seals, you start out with a lovely additional 126 health.

Other Possibilities

As it stands the only other runes I'd consider using are the new energy regen or energy increasing runes that are, unfortunately, unable to be linked.

Greater Quintessence of Meditation
+1.575 Energy regen/5 sec

Greater Quintessence of Acumen
+5.4 Energy

Greater Seal of Lucidity
+0.063 Energy regen/5 sec per level (+1.15 at lvl 18)

Greater Seal of Meditation
+0.63 Energy regen/5 sec

Greater Glyph of Sapience
+0.161 Energy/level (+2.9 at lvl 18)

Greater Glyph of Acumen
+2.2 Energy

21/6/3
Reach the bottom in offense for the bonus damage. I take minion damage as well since early game Lee has some pretty weak abilities that I always misjudge. The points in defense are purely for some survivability and lastly I had three points left for whatever so I thought, "Meh, if I die I want to come back and kill someone sooner." Now this is just my thoughts on a decent mastery build, but it should cover the main function of your character, in this case AD, and then make it so his now increased main function won't be shutdown, hence getting more defense and returning sooner to the battlefield if you do end up getting shutdown.

Your opening depends on how you like playing the most, risk versus reward. Preferably I'd go with a for its bonus health and regen. You could also go with a and if you wanted to try for a more aggressive opener, completely up to you. Anyways back to whats important, you'll want your next major purchase to be . I find that, in most games, the other team gets quite a bit of cc making these a must have because of the tenacity patch, the magic resist is also an added benefit. Next you should definitely get a . Since all of Lee Sin's abilities have a second effect this is a great buy early on for some impressive damage output. I'll explain: take his Q for instance, its follow up is another attack. With the Sheen proc you can dash in for another massive hit. But thats not all, say you dashed into an ally to give him your shield, well now you have a Sheen proc and your passive ready just begging to be used, its a win win either way. Now after your Sheen I'd suggest rushing to a to complete the item, but you could just as easily get a first if you're low on money. With the Trinity Force you'll get some health as well as a lot more damage added into your combo, so with that in mind buying a will maximize your damage at this level. After that you should get some more survivability and a is pretty much all around beneficial (except for mana obviously), and lets Lee take a little more of a beating in team fights. Now that we can survive better its back to making us more of a threat, building a gives more attack (55 more with all the minion kills) and some nice life steal that works well with your W. Now that we're back to doing more damage getting some more health will definately help in the long run, works nicely for health, some much needed cooldown, and a little bit of health regen. Then to top it all off building a will give increased damage, speed, and, what we're really after, some armor pen. With Lee's passive applying the stacks will be incredibly easy.

So a quick recap:
for good opening health and regen
nothing beats magic resist and some anti cc, plus you don't need attack speed
the proc is amazing
better proc, health, move speed, and attack
triforce gave health, this will maximize early damage
back to getting more health, magic resist, and a nice passive
turn the b.f. sword into something useful
good health, cooldown, and health regen
good attack, attack speed (some does help), and great passive

Now this is fairly similar to the recommended items for Lee Sin, which means Riot does know what they are talking about. I, however, found that getting more health, cooldown, and attack make for a more potent in your face Lee than one that will flee as soon as he's targeted.

Sonic Wave / Resonating Strike

Sonic Wave is a skill shot nuke that reveals the enemy it hits. Deals a decent amount of damage by itself and is good for checking brush as it can reveal entire ganks waiting in one bush. Resonating Strike is the follow up to Sonic Wave and must be cast within 3 seconds. This lets Lee Sin fly to the target with a leaping kick to the face. Great for initiating and dealing good harass. Both these abilities scale off of AD. Deals physical damage.

Safeguard / Iron Will

Safeguard lets Lee dash to any allied anything (except for turrets and inhibitors) and provies them both with a shield that increase based on AP. Great for mitigating damage from dots and dashing out of ganks. Iron Will is the follow up to Safeguard that must be cast within 3 seconds. Activating this gives Lee Sin additional life steal, spell vamp, and armor for a set amount of time.

Tempest / Cripple

Tempest is Lee Sin's AoE ability that also reveals enemies he has hit with it. Deals magic damage and scales off of AD. He can then cast Cripple within 3 seconds to slow the movement and attack speed of nearby enemies he has hit with Tempest. Cripple and Tempest don't have the largest range but Tempest does the largest amount of AoE damage.

Flurry

Passive: After Lee Sin uses an ability he gains Flurry that increases his attack speed by 50% for his next two attacks. These attacks also regen 15 energy each.

Skill Sequence



Why so little W?
Honestly it doesn't do anything to help with killing people until its later ranks making it pretty useless early game - save for escaping ganks and shielding teammates - so I focused more on the whole doing damage aspect. Plus with the point at 4 its still viable for some early defense with trying to harass or protect yourself from harass.

Q over E
Both these abilities are pretty useless in their early ranks, but Q is great for easy harass and initiating a team gank. E does some great damage eventually but its the slow we're after when I pick this spell early on and master it second.

I choose Flash and Cleanse as my summoner spells.

Flash

This is a god send regardless of who you are using, can't go wrong with this one.

Cleanse

I choose this one for Lee as my last resort "Oh shi-" button, with W and R alone you can get away from just about anything.

Other possibilities:

Ghost

Another great one for getting away or catching up to people, can't go wrong with this.

Teleport

I honestly don't use this at all, but it does have its advantages in certain situations that could make it more appealing to some people

Heal

OMG you're such a noob for using Heal! Yeah, tell me that again when I survive your all-out combo and then kill you. People seem to hate this spell when really its a great idea to have it. Its only downside is late game when its pretty much useless.

Exhaust

Another one of those can't go wrong spells, although Lee does have his own exhaust, having another one will mean you won't be leaving anytime soon.

Ignite

This is to insure a kill. Ignite someone who is low on health and fleeing and you'll more than likely get the kill. Doesn't mesh with any of Lee Sin's abilities but it certainly has its uses.

Anything else is trivial.

Pros:
Great early/mid game potential
Q-E combo can do massive amounts of damage early game
Passive removes the need to purchase attack speed
Can very easily get away from a dangerous situations
Extra health makes surviving mid/late game much easier
Great for revealing hidden enemies
Part Chuck Norris


Cons:
Hard to master energy use and consumption in team fights
Ult requires placement to be effective
Less cooldown with more offense
More weak to physical attacks
Late game is a bit tougher to do max damage

Lee Sin can actually support his team very well with three of his abilities.

The most obvious of his three "support" spells. Mid game your team will probably hate you for how little it does, but early and late game see a much bigger increase in effectiveness making it possible to mitigate most damage from DoTs and fatal blows.

Very helpful with with teammates. If you're close to someone your team isn't, just do a double tap and let your team catch up to him/her and pick up an easy kill. Its also helpful in team fights when everyone is together, if you can get everyone with cripple (or at least the AD carry's) they will be pretty useless to their team for that part of the team fight.

Dragon's Rage works well when you're grouped up with teammates. You can use it for multiple situations, flashing past a fleeing enemy to knock him back into your team, knocking the tank back through his team dealing massive damage to everyone, or even using it to save your team when fleeing, that'll teach them to follow in a straight line.

Early Game
Early farm is annoying for Lee Sin, his Q doesn't really help except for one target and his E is fairly weak in the beginning too. Last hitting is your best bet, and once you hit level 4 you can retreat a heck of a lot easier too. Also using your abilities to get your passive when trying to kill minions makes it easier and faster for clearing our a group if you can time your abilities to use his passive to its fullest.

Mid Game
Mid game starts to pick up for Lee when his physical attacks can start dropping minions faster.

Late Game
Finally late game he can pick up almost all the kills with his E for some easy money when trying to finish up the last few parts of your build.

Some champions have a fairly difficult to use passive at times and Lee Sin is no exception. Here's out it works, after ANY ability you get two hits that attack 50% faster and regen energy for you, nice. This is great for just about any scenario:

Attacking minions:
Attack with an ability, 2 hits, use second part of ability, 2 hits, next ability, repeat. Makes farming much easier for Lee since he's a little lost in that department

Attacking a champion:
Same principle, although you'll probably be spamming your abilities. MISTAKE. While the buff does reset after every spell use, you'll be wasting more energy then regening leaving you pretty useless if your target gets away. If you want to utilize it you have to space out your abilities.

Attacking any structure:
When I thought of this a nice little smile came across my face. Since I don't build Lee Sin with attack speed purely because of his passive I got a brilliant idea, using your abilities while attacking a tower will still proc your passive. Meaning you'll get the increased speed and your energy will regen off of your attacks as well. this lets you take down turrets faster and still have energy enough to get away if necessary.

The timing of this passive is key, and, while harder to use on other champions, lets him participate longer in team fights then some of the other energy users.

QQ more with battle cry
Basically Q-Q is the most damage you'll do early game so here's what you do, hit someone with Q then when you press Q and are flying through the air let out a battle cry (but if you have to save yourself from embarrassment thats cool). This makes the move seem much more important and deadly plus its just hilarious to think about.

Greatest ult in existence
First: Its a roundhouse kick...
Second: Insta-kill low health champs for easy ks or finish
Third: Kick someone through multiple people, possibly netting a kill (this also deserves a battle cry)
Fourth: Kicking someone for no reason
Fifth: Flash kicking, so brilliant and so deadly
Sixth: Kicking the tank for no reason...cause you hate him
Seventh: Did I mention the roundhouse? I mean, come on, its in the ability description

April Fools
Associated with the April Fools champion spotlight. Basically whenever you do something just think, "Because I'm Lee Sin, the Blind Monk."

Whatever you do is worth it
Because you said so in chat.

With this build you'll build a more sustained DPS version of Lee Sin instead of incredible burst and squishiness. I hope that if you like Lee Sin and are looking for a new way to pump up his game you try out this build. I refuse to post game scores for the sole reason of I have no need to impress you or show you fake pictures. If you have any tips on ways to improve this build or the look of the guide please let me know, I found I quite enjoy making these.