Hello and welcome to a quick and simple guide to the Leblanc, the Deceiver.
Leblanc is a ranged dps nuker champion, she is at her prime early to mid game (level 5-16) and is very powerful if used correctly.
Build above is based on the assumption that you want a straight offensive nuker, with still quite a bit of get-away ability for those tight jams we seem to get ourselves into.

Going just far enough up the Offense tree to get a point in Archaic Knowledge is the best decision you can possibly make when choosing masteries.
Using the rest of your points you should fill up the utility tree trying to maximize cdr and mana regen.
I consider this quite a standard AP mastery build.

As for items Rabadons Deathcap is a MUST for ALL Leblanc players who wish to do anything during a game, I prefer to rush it myself by simply buying boots and a potion or two to start and to extend my laning time in order to farm enough minions.

After that Deathfire Grasp is a redicoulously amazing item in that it both gives you AP (which of course rocks especially with rabadons) and it also gives you a 30% true damage attack (i commonly use it to open on an enemy, bringing them to 2/3 health immediately).

At this point if your opponents start wising up and trying to build their magic resist you have the perfect weapon at your disposal, aka the Void Staff, its ap is quite complementary and the 40% magic penetration is unbelievably helpful in every battle.

Beyond the Void Staff its pretty much up to you what you would like to build, I like rylais Crystal Sceptre because it gives your attacks an additional slow when you attack anyone with your magic spells (1.5 seconds of slow can make quite a difference trust me!)

If the game is still going somehow after you have nuked all their players into the ground at this point its really up to you, im a power kinda guy so i go straight for Zhonyas Hourglass, because i mean come on, 100 ap rocks, seriously, and the passive can save you if you are focused, atleast temporarily.

Sigil of Silence Sigil of Silence Sigil of Silence.
Maximize this skill as fast as possible, it is your top damaging spell and it is just plain devastating to enemies no matter who they are.

Some Leblanc builds swear by Distortion, but i prefer leveling Ethereal Chains first, and heres why:
1. Ethereal Chains both slows and then stuns an opponent upon hitting them, assuming you stay withing range
2. Chains also does damage, both when it hits and when it stuns, making it all the more powerful.
3. Chains can be thrown on an enemy as you run from them to slow and/or stun them to get away.

Distortion should be leveled last, but dont underestimate it, as it can be a great follow up move after your Sigil of Silence lands in order to activate the Sigil.
It is also an amazing movement/escape tool, i have escaped numerous times using Distortion followed by a Mimic of Distortion and been completely scott free of the enemy.

If you are not familiar with Leblanc, and he abilities, you soon will be.

I personally love playing mid as Leblanc because you can temendously destroy a unsuspecting enemy who has pushed up too far with a simple W>E>Q>R and if they are still alive then another Q should do the trick, or Ignite works too.

When engaging in a team fight always hang back and let someone else like the tank initiate, and quickly focus their most dangerous dps character, If at this point you have your Deathfire Grasp I highly recommend using it to cut their HP significantly off the start, following up with a Q>R>W.

If you do not have your Deathfire you will need to be a bit more hesitant and maybe try and pick off a straggler on the end of the fight or running away and use your W>E>Q>R combo to get them down and gone.

Also just plain focusing who your team is attacking will quicken the process significantly, allowing your team to clean up the rest of them one after another.

Please also note that Distortion can be used to jump over/through small walls or cliffs.

As for summoner spells I always use both ghost with the point in the mastery tree, as well as flash.

Ghost is simply amazing for getting anywhere faster, whether its towards or away from enemies is your choice.

Flash can get you out of a bind and over a wall, or it can be used to finish off an escapee when your Distortion is on CD.

Ive seen plenty of builds using Ignite, which is also viable, as it's DoT can finish off runners who get within tower or enemy champion range.

Teleport is also good for soloing mid as returning quickly is a must.

Exhaust can be useful if you are not 100% confident in your ability to connect with your chains, or can just plain disable a AD champion from both dealing damage or escaping for the most part.

Do not get clarity, trust me, Leblanc may have early game mana issues sometimes, but thats why you have masteries, and it becomes useless late game.

In conclusion i hope you guys find this guide and build useful, I sure as heck do, and i hope that you will enjoy the nuking abilities you will have.

~Gbonus4