Hello! My name is G3P (twitch.tv/g3p_) and I was a Diamond elo player that peaked D1 during season 6 and have gotten multiple of my accounts to diamond playing Leblanc. I feel as though I have learned some things about her and I hope to share every bit of what I have learned with you and assist you in gaining elo regardless of rank. If there is anything that is unclear or if there was a matchup that I didn't go over and you would like clarification on please comment and I will update the guide.

Super important item against any team that heals. Normally it's an item that is built second in the build path. Not only does it reduce the healing on enemy champions so you can burst them quickly, it also gives Leblanc some tank, which is very important because Leblanc throws herself into most fights and is not crazy long range.

Sorc Boots are a somewhat more obvious build path. Building early increases your damage in trades and your ability to roam. Can build first, but only against champions where movement is essential. I'm talking about playing against TF to get away from his card, Olaf to out run him, champions with skillshots where you need movement speed to dodge them.
+ ARE THE BREAD AND BUTTER OF LEBLANC. These items allow leblanc to become a destructive force. Giving her the ability to one shot carries and snowball leads. Ludens is always the first item in the build path, it gives you so many good stats like mana, ability power, and CDR. CDR is god on Leblanc, it's all about having high mobility and CDR enables that so much.

This item is god against AD mids like yasuo, zed, and talon. If this item is used correctly it can negate their all in and I would advise building it first or second against all AD assassins(not AD carries like ezreal). Hourglass or Banshees should always be a build item on Leblanc. It allows her to make aggressive plays and live through it. Getting caught by cc or just trying to dodge a global ult hourglass helps the squishy nature of Leblanc. Also later in the game her W cooldown is so short that by the time her hourglass turns off she can W out of most situations(unless caught by cc).

This item is so strong against comps that have any mr. Although it is situational when to build this item. Most of the time I find myself building it third or fourth. Depending on how much mr is on the other team(which is something you should be checking through out the game). If my lane opponent builds any kind of mr as their first item or a jungler rushed an early MR item then I would build Void Staff second. And I mean crazy tanky MR items like visage. Keeping your assassination potential up is a must to create pressure on the map.

SKILL ORDER:
I do describe this under the notes page on the skill order, but just to be clear. Taking your E third and your Q first is usually a bad idea. The reason being that early game Leblanc has high mana costs and trading with 3 abilities early game can make her go oom very quickly. Not only that, Q draws minion aggro when used on a champion. Instead of putting that extra point in E I suggest putting it in W. The reason being that Leblanc is a roaming champion and she has poor wave clear. She is strong when she is roaming and in order to do that she has to clear the lane quickly so she cant return before the enemy laner has a chance to clear the wave and make you lose cs. Clearing the wave quickly can also create pressure on the other laner to farm under tower or to prevent an all in from the enemy laner because of you having the advantage in the minion wave. The rest of the game I suggest maxing W for wave clear and roam and then Q for the burst.

Skill Sequence:
Early game pre 4 your combo will be Q + W. ALWAYS MAKE SURE TO AUTO BEFORE YOU W BACK IF YOUR OPPONENT DOESN'T HAVE HARD CC. Early game autos are strong and do a lot of damage. They can win trades because people underestimate them on AP champs. This combo is very strong early game and can win trades against most mid laners without shields. Once you put a point in your e it's all about hitting the chain. Whether that's in a trade or if you have a jungler coming into gank it's about landing your chain. If your opponent is out in the open E first and then go in for the Q + W combo. Walking up after your chain lands is also a must. This is because if your enemy flashes then the chain will still be on them. Making it impossible for the enemy to escape. Later in the game though you probably won't get the chance to get close enough to land your chain first. This is when your W comes into play. Late game your W becomes a gap closer. The combo to dive in from a flank and attempt to kill a carry will be W + R + Q + E. The reason the chain is after the Q is because you most likely won't have the time to let the second part of the E to go off. So activating the sigil with your E at the end will kill most carries late game or create enough pressure to zone the enemy off of objectives. The key is being fast though. Practicing this combo over and over can win you games off of one play.

There are really only two more combos to leblanc. The first one being the "One shot". This combo only works if you have vision control or at lower elo. The thing about this combo is that they have to be close for it to work. This combo is Q + R + W. Some people might question why I don't throw out the chain and that is because it will give them more time to react. If I know they have flash or if I know I can't one shot them with just Q + R + W then I will throw out the chain FIRST encase they do react and flash away then my chain will still be on them.

Overview:

Basic Combo: (Early Game)
+
Pre Level 6, Post Level 3:
+ +
Late Game, Assassinating far away carries: Q And R can be interchanged
+ + +
One Shot Bush Check: (No Flash and are squishy)
+ +
One Shot Bush Check: (Have Flash or tanky)
+ + +

Very Important to have. For safety after you blow your W and R; Also to make aggressive plays. When people play against leblanc they usually don't expect her to do that much damage. Once they understand this then they play back away from Leblanc's range. Lets say I just out trade a Xerath and he is playing back from me (pre 6). Flashing foward and then Q + W or just W AA ignite would kill him. The flash catches people off guard and is very important on assassins.
The go to spell for assassins. Gets kills and snowballs leads by itself. Very important to secure kills and to gain advantages. Burst champion needs a spell that does damage.

Leblanc is an assassin and does not have as good aoe or range as other mid laners. Knowing this you have to understand that grouping is almost always a bad idea with Leblanc. Unless of course you are sieging or countersieging. Even with objectives you should be establishing ward control before you want to go for said objective and then try to get picks. Leblanc is the master at taking people down 100 to 0. Use that to your advantage to secure important objectives after getting a pick. Playing Leblanc by sieging isn't really the best way to play her, playing on the flank, roaming, and establishing ward control to get picks is what Leblanc is all about. Also just keep in mind that wards win games. If you know everything that the enemy is doing then how can you ever be in a bad position? Which brings me to another point. LOOK AT YOUR MAP. All the time. You should be glancing down at your map every few seconds to know where their jungler is or who is pushed up. This is because leblanc is very good at roaming. If your Ashe, Vel'Koz lane is getting shoved in bot by Cait, Sona then you know it should be an easy roam down bot lane. Although, don't go the usual route. Use your W to dash over walls and be unpredictable. This increases the chance that you won't be seen by a ward. You could even come up in lane because leblanc has insane gap closer. More than anything, play aggressive. Leblanc is strong because of the leads she can get and her mobility. Being fed just makes these strengths even more apparent.

Another important aspect is where to place wards. Try to figure out where their jungler is starting. To do this see who comes to lane first top or bot. Whoever comes late is most likely where their jungler is starting. Although, you should also take into account what champions are top and bottom. Determining where their jungler will be once he hits lvl 3 will determine where you place your ward. Try to place your ward where it will see paths from the river, and from the enemy's camp. The corridors that lead to dragon and baron are the best places to see. Champions that can dash over walls will still be spotted out and make sure you're warding towards important objectives that you want to take. For instance, if you want to take bottom tower try to establish ward control in the bottom jungle, do this with your support or jungler and communicate that you're doing this, or if you want dragon then set up wards both in dragon and around it.

Leblanc is very easy to gank for. Because of her gap close and chain she can lock down almost any target who is far away from her. Although you should communicate to your jungler when certain abilities are on cooldown. Like an important stun or a flash. Anything that could make a gank not successful should be communicated before the gank. Also all other laners should be accounted for. If the other team has good vision control and their top riven is missing then it is not a good idea for your jungler to go in because riven is probably sitting on the other side of the river and your jungler is probably sitting on a ward. BUY CONTROL WARDS AND CLEAR WARDS. Especially before objectives come up. Having ward control is having the power to take objectives and to create picks for your team.

BLUE BUFF
One thing about blue bluff is that it is extremely important on leblanc. Another thing about blue buff is that leblanc is very good at killing it. Once you hit 11 you can solo blue buff without your jungler. It might be tedious, but having blue buff allows you to roam and to spam poke against the enemy mid laner. Mostly roaming. This is because it's great if you win lane and everything, but if you roam bottom and that ashe, vel'koz lane gets a kill then it is going to make it a lot easier to win the game by snowballing not just yourself, but your team.

The csing for this champion is fairly basic. For caster minions you will have to AA them before they come under tower AA then Q or AA them after they get hit by a tower shot. Melee minions will still die from one auto after taking two tower shots early game. Later in the game you will have to use more abilities to farm. Getting all of the minions low and then using your W to one shot them is also a common technique. Although, if all of the minions are at full health and your team needs you, W+R is a quick way to clear the wave and move to help your team or to get a fast back in. The 10% attack speed helps a TON with csing and makes it a lot less painful; It's also very nice in trades early on in the game.

Play aggressive. Really. Leblanc isn't one of those late game champions who will become God when they hit 3 items(KASSADIN). She is all about winning lane and snowballing leads. If you have any questions about my guide or would like me to add more please feel free to comment. Thanks and stay safe.