Ok people all over the world. Here is the killerguide for Leblanc. First I try to explain why this build is exatly how it is.
Mastery Tree:
Im using all into Damage because she doesnt need def or resistance, because she can port 3 times away and i think if you are a good leblanc player it is possible to run away from every situation. first time with the W-Skill, then Ulti and if you cant get away use your flash.
Skill Sequence:
the skilling sequence is build on the Q-Spell. It makes a lot of damage, because if you aim on the enemie it damages everytime. The other skills are more dangerous and you never damage the enemie everytime. So first build the Q-Spell to maximum then W and then E. Of course R-Ulti everytime if its possible.
Rune Build. The Rune build is made on magic pen. Because in the end you need magic pen and there are only few items with magic pen. Ability power in the beginning is very nice to kill enemies very early.
Item Purchase.
The first thing for a good leblanc player is mejas soulstealer. If you a noob, Pls dont buy it and use another build without it.
then we need buy shoes to run faster. avoid damge you get if you have no boots. Then for me its important buying a bit mana with TOTD. In the end its a lot of ability power you get. combined with rabandons cap its overpowered i think. for a little bit more hp and mana i buy ROA. Of course the ability power helps us to kill enemy fast. the void staff in the end is helping to penetrate tanks or people who are angry of you and buy magic res. so you can penetrate their magic res really hard.
i think this is enough. have fun killing all enemies. i always win in the mid with this build. good luck have fun :)