First, let me note that the recent LeBlanc hotfix hampers her effectiveness a bit. From the website:

"For Q-R the following changes:

* Reduced the initial damage on Sigil of Silence to 70/110/150/190/230 from 80/125/170/215/260.
* Reduced the cast range on Sigil of Silence to 700 from 750.
* Increased the cooldown of Mimic to 40 seconds from 30 seconds at all ranks.
* Reduced the damage amplification on Mimic to 10/25/40% from 20/30/40%. (The tooltip was incorrectly stating 20/35/50%).


To address her mana efficiency we made the following changes:

* Increased the mana cost on Sigil of Silence to 70/75/80/85/90 from 60/65/70/75/80.
* Increased the mana cost on Distortion to 80/90/100/110/120 from 60/70/80/90/100.
* Increased the mana cost on Ethereal Chains to 80 from 70 at all ranks.
* Reduced her mana per level to 50 from 56.


We made two minor changes in addition to the ones noted above. We reduced her armor per level by 0.5 since melee need to feel she's appropriately squishy, and we reduced the damage of Distortion and Ethereal Chains by 5 at all ranks to preserve Q's position as the highest damage output ability and not adjust skill choices."


She's still incredibly playable. You just have to tweak her playstyle.

This will not be a guide to playing basic LeBlanc. This guide will not cover what her skills do. Instead, it will suggest a different way to play her.

I used to be one of the people who would rush a pure AP LeBlanc. This meant rushing Archangels Staff, Zhonya's Ring (before it got removed), a second Archangel's Staff, etc, all to break, say, 700 AP. The problem with that is that LeBlanc becomes increasingly useless late-game. If an opponent buys a single Banshee's Veil, they've just reduced the power of your burst by around 600-700 magic damage. Enemies who start to stack Magic resist against you will be much harder to take down, and many of you have probably noticed that players tend to buy these items late-game as they notice how prominent of a threat you are.

Then what? Now the items that you've invested in your AP don't accomplish much. Your spike may take down about half of their initiator's health, or may kill a squishy. After that, you're useless for the next 10 seconds or so, until Distortion recharges (Sigil by itself won't be doing much damage). In that time, you're left with a weak auto-attack, no escape method, and generally will be focused down fast with little to no magic resist or armor.

TL;DR: While LeBlanc may be powerful early-game going pure AP and magic penetration, she will quickly become useless late-game and will often be the first to be focused down in a team fight. Without some utility or survivability, she won't get anything accomplished.

Ranting aside, the actual guide portion of the guide begins here.

Runes

The rune build focuses more on cooldown reduction than on actual magic penetration. The Quints and Glyphs, combined with your masteries and item build, put you at just about 40% CDR, the maximum you can achieve. Since you only require 2 Quintessences to do so, you can place the last one in magic penetration.

I made an error earlier when writing this: 40 magic penetration is the maximum you can achieve from items. You can exceed that amount with runes.

However, I find that it is more useful to get to the 40% cooldown cap instead of pushing for magic penetration as your utility will be far better late-game. If your Glyphs and Quintessences were shifted to Ability Power or Magic Penetration, you would have to buy, say, a Deathfire Grasp to get to the 40% CDR cap.

Masteries

The masteries are rather standard for a caster. I do choose to forgo the 15% summoner spell CD in favor of increased ability power on Ignite. However, you can always go 9/0/21, if you so choose.

Summoner Spells

I choose Teleport and Ignite as my summoner spells. Early game, LeBlanc does enough burst damage so that she almost never needs to chase a champion down with Ghost, Exhaust, or Flash. Teleport is used to make your mid-game phase much easier and to obtain more stacks of Mejai's. The spell has proven to be extremely effective time and time again.

The only skill I would recommend taking over Teleport is Cleanse, as with Cleanse+Distortion+Mimicked Distortion, you can get away from just about anything. Without Cleanse, you can sometimes be silenced or stunned and thus rendered unable to get away. Still, I prefer the mobility of Teleport over anything else.

Ignite is essential for capturing that first blood in mid lane. You'll read more in the combo section later.

Skill Sequence

Put one point in Sigil of Silence right out of the gate. At level 2, grab Distortion. Max Sigil of Silence first, then Distortion, then Ethereal Chains, grabbing Mimic at 6, 11, and 16. Pretty standard skill order. While some builds tell you to max Ethereal Chains, then Distortion, I go the other way. This is simply because Sigil of Silence+Distortion is a far more reliable harass than Sigil+Chains is.

Item Build

Get a Sapphire Crystal and two Health Potions right away. With the nerf that LeBlanc received, her combos are more mana-heavy in early game, and you won't have the mana to continue a harass or to push for first blood if you grab Boots. While getting Doran's Ring is an option, Sapphire Crystal is preferred because you can rush Catalyst after getting first blood, or at least a kill.

On your first trip back, it is essential that you purchase Catalyst the Protector. If you have to forgo boots for it, so be it. Catalyst gives you incredible laning power, which is important for a character that is so strong in the middle lane. Ideally, you will have enough money for both Catalyst and Boots of Speed on your first trip back (a sum of 1325 gold).

Grab Mejai's Soulstealer as soon as possible after getting your Boots. If you can afford it, finish Sorcerer's Shoes on the same trip (2035 gold total, only 1385 for Mejai's).

Now, depending on enemy team composition, the next few steps are variable.

When facing a caster-heavy team:

Get a Negatron Cloak first. If they lack a large amount of spike damage (Fiddlesticks as an example) then finish Abyssal Scepter. However, if you face an enemy LeBlanc, Ryze, Annie, or Veigar, now is a good time to complete Banshee's Veil right off the bat. Afterwards, get Glacial Shroud, THEN finish Zhonya's Hourglass, and finally complete Frozen Heart.

When facing a melee-heavy team:

Skip the Abyssal Scepter for now and go straight for Glacial Shroud. Finish Frozen Heart as soon as possible; the armor and the decreased attack speed will save your life, as will the lowered cooldowns. If they have a champion where it is essential to dodge one of their abilities ( Mocking Shout, Rupture, or Cryptic Gaze) finish Banshee's Veil. If not, you can actually branch off into a Rod of Ages. In either case, finish Abyssal Scepter, then Zhonya's Hourglass afterwards.

Combos and Playstyle

Early Game

Take the middle lane right off the gate. LeBlanc is fantastic at solo-laning because of her single-target burst and harass. If you don't take mid, you won't be strong enough in mid-game to start ganking side lanes with ease.

At level 1, it is important to play conservatively. DEWO, you'll hate me for this, but I am still advising to not harass with only Sigil of Silence at level 1. Especially considering that the mana cost has been boosted from 60 to 80, simply harassing with your Q is not worth it when the majority of your early burst damage comes from a two-skill combo. When the time comes, you won't have enough mana to harass or go for first blood, even with Sapphire Crystal.

Once you hit level 2, harass with Q+W+W whenever possible. That is to say, fire off Sigil, jump in to trigger the Mark with Distortion, and Distort back out to where you casted from. Once you see their health drop to 40% or so, most other mid laners will still be cocky enough to stay and fight, reluctant to lose experience. This is where you punish them.

Played right, you can often kill an overconfident enemy by level 4 or 5 with a combination of your Q and your W, bringing them to roughly 20% HP. As they flee, cast Ethereal Chains on them to slow and immobilize them. Ignite, autoattacks, and recasting Sigil on recharge should be more than enough to kill them and hopefully nab first blood for your team.

Basic Harass
Sigil of SilenceQ--> W--> W

Combo summary: Throw a Sigil, teleport on them, teleport back out.
Mana cost: 150 at level 2 to 210 at level 13
Damage: 175 at level 2 to 235 at level 3 to 295 at level 5. Scales with 1.5 of your Ability Power.
Cooldown: 20 seconds (16.64 seconds with Runes+Masteries) (12 seconds with Frozen Heart).

while your Finisher is:
Sigil of SilenceQ--> W--> E--> Ignite-->Sigil of SilenceQ.

This deals roughly 170-200 magic damage plus an additional 130-150 true damage from Ignite.

Mid-Game

I define mid-game for LeBlanc as whenever you have Mejai's Soulstealer. You should be level 7 or 8 by now. The most appealing point of this is that you now have Mimic available. This opens a world of new combos that were previously unavailable.

Advanced Harass
W-->Sigil of SilenceQ--> R--> W

People normally don't expect this combo. In solo mid, your laning enemy will eventually notice that you can only harass once you get in range for a Sigil+Distortion combo. They'll usually feel safe once they're comfortably out of range of Sigil. This combo exploits that by teleporting in and throwing, essentially, a double Sigil on them. It's pretty great for harass and is extremely unexpected. You can also use this combo to surprise a low-level squishy that's already low on health.

Combo summary: Teleport in, throw a Sigil, throw a mimicked Sigil, teleport back out.
Mana cost: 260 at level 6 to 280 at level 9 to 240 at level 11.
Damage: 370 damage at level 6 to 583 damage at level 9 to 617.5 damage at level 11. Scales with 1.56 / 1.65 / 1.74 of your Ability Power, based on Mimic's level.
Cooldown: 40 seconds (33.3 seconds with runes and masteries) (24 seconds with Frozen Heart)


Bread and Butter
Sigil of SilenceQ--> R--> W--> W

This combo is your primary combo for spiking down an enemy. It's obviously harder to pull off than the previous combo because you must be in range, and they'll have time to react. However, when used from the brush under the top left corner (or the brush above the bottom right corner) to gank the two side lanes, you can easily assassinate an enemy laner. At the end of the combo, you have the option to flash back by pressing "W" again or to pursue with your E, Ignite, and Sigil of Silence, once it recharges.

Combo summary: Sigil, mimicked Sigil, Distort on top of them.
Mana cost: 260 at level 6 to 280 at level 9 to 240 at level 11.
Damage: 531 damage at level 6 to 818 damage at level 9 to 907.5 damage at level 11. Scales with 2.49 / 2.63 / 2.76 of your Ability Power, based on Mimic's level.
Cooldown: 40 seconds (33.3 seconds with runes and masteries) (24 seconds with Frozen Heart)

Run! (Nuke!)
W--> R

Simple enough, really. In an event where you're ganked or are about to be ganked and you have both your W and your R ready, you can almost always flee from a battle with Distortion and a Mimicked Distortion.

You can also use this combo to rapidly approach a tower under siege if your Teleport spell is on cooldown. You will close roughly 20% of the distance extremely quickly with dual Distortion.

Try not to use this offensively. While it may be area-of-effect, the damage is negligible without Sigil of Silence to back it up. At level 16, you will deal around the same damage as your "Bread and Butter" combo does at level 6. The only case where it is acceptable to Dual Distort under offense is to quickly catch up to an enemy champion that is at extremely low health, to then hit with a Sigil+Ethereal Chains combo.

Also, as strange or as wasteful as this may seem, this combo is extremely effective at clearing minion waves at high ability power. It is especially useful for clearing out mobs of bunched-up caster minions.

Mana cost: Anywhere from 120 to 220 mana depending on how much you've upgraded your skills.
Damage: Unimportant. Usually takes 150-200 AP to be able to clear caster minions in one hit.
Cooldown: 40 seconds (33.3 seconds with runes and masteries) (24 seconds with Frozen Heart)

Late-Game
Stick with your team at all times. In a team fight, target their most important character and use your "Bread and Butter" combo on them. In fact, if you have Frozen Heart, you can cast Sigil of Silence on recharge to trigger your Mimicked Sigil of Silence again. The silence itselfcan last for over 6 seconds if timed correctly, and you can essentially shut down one of their support characters (Morgana, Lux, Janna). Chase down runners with Distortion and Ethereal Chains. Support the team and don't die; retain your Mejai's stacks for as long as possible. You should push your team to victory easily with your burst damage and crowd control.

FAQ - Why Zhonya's Hourglass over Rabadon's Deathcap?


The Hourglass gives you better survivability over AP, and since you'll be a mainly CC-oriented champion late-game, you do NOT need the extra AP as much as you need the extra survivability. Honestly, though, it's up to you. If you feel that you need the Deathcap, go ahead and buy it.

Summary

This guide is designed to utilize LeBlanc to her fullest potential in early, mid, and late-game. Early game, she shines as an assassin, ganking and gimping side lanes while accumulating Mejai's stacks. Mid-game, she is the tide-turner of team fights, taking out their key squishy and getting away to live another day. Late-game, she has incredible crowd control with a substantial silence skill, a slow, a snare, great chasing ability, and still retains very nice burst damage. Couple that with the mass magic resist lowering from Abyssal Scepter and the decreased attack speed from Frozen Heart and LeBlanc is one of the best late-game utility characters there is.

While pure AP LeBlanc is still perfectly viable in lower-level play, I highly recommend this build to any and all players unhappy with their K/D ratios when playing LeBlanc. Throwing out a statistic: I averaged about 60/40 as a win/loss ratio when I played AP LeBlanc. I haven't lost a single game with this build.

Have fun with LeBlanc. Make people scream "OP NERF" on an already-nerfed champion.

Bonne chance!