Ok, so this guide is for those who love playing Ahri but are having a hard time playing against other champs who "counter Ahri". Champs such as Annie, Ryze, Veigar, Fizz, Viktor, Akalli, Kassadin... etc. With this combination of AP masteries/runes and tanky items, you'll be able to own any mid. If you are playing against a champ which isn't known to be a natural Ahri counter stick with more common builds w/o the early Giant's belt nor Banshee's. So yeah, I hope this build works out for you guys and that you help me convince people that Ahri isn't as easy to counter as people think.
Ok, so for Runes I go crazy AP/Magic Pen. I go for Magic Pen. marks, flat AP seals, flat AP glyphs and ability per level quintessences. The reason for these runes is quite simple, you'll need as much AP early game as you can, since you'll be getting tanky as hell (for a mid)with Giant's Belt and Banshee's.
Masteries are standard AP, 21/0/9 taking all AP offensive masteries,along with CD reduction and increased damage. Utility I get flash CD reduction, increased Mana, increased Mana regen, increased movement (for filling the gap) and increased buff time.
You may ask, why get utility masteries if the very sense of this guide is to make a tanky Ahri? Well simple: MANA!! Your passive along with revolver will keep you in lane forever, spamming fox-fire to reach the 9 stacks ASAP with low mana requirements, then orbing to heal will keep you alive for ever. More on this further on.
So... what's the thing "Ahri counters" have in common? Crazy burst damage, killing her before she has time to heal with passive. There's where Giant's Belt hops in! It's of vital importance to get this item before enemy gets to level 6, this way you can resist any combo they send to you even if you are getting ganked.
After Giant's belt, rush Banshee's Veil. And... congrats!! You are invincible, no gank nor attack from your enemy champion will kill you, just make sure you have Spirit Rush or Flash up at all times, try not to use them at the same time.
After you get these 2 items, it's pretty straight forward. Revolver to enhance your passive, Rabadon's because a mage w/o it just sucks, then build Rylais from that Giant's Belt for increased tankyness. After these core items, the rest of the build is quite situational, enemies probably won't build magic resistance since you'll have low AP until you get Rabadon's, so it's not worth it to rush for a Void Staff or other magic pen items. If you do need magic pen, get Void Staff before Rylai's and if you need even more then sell that Revolver and get Abyssal for late game. If you are still getting pushed or getting ganked like crazy, you can get Catalyst right after Banshee's and turn it to RoA before getting Rylai's. It's important to get RoA early (if you are getting it) to make full use of it's passive which is awesome for low levels.
Skill sequence is also quite straight forward, your main source of damage is that pretty Orb you have in your hand so you'll want to max that skill out ASAP, get one point on charm early but max it out last since it's mainly utility and CC no dmg output from that. Fox-Fire is not less important since the damage output is also awesome and it's quite useful for killing fleeing enemies but I max it second in order for it to demand less mana and be able to spam it for stacks. And of course get ulti at level 6/11/16.
The thing I love about Ahri the most is her versatility. Most champs have a set combo which has to be timed perfectly in order to work, Ahri can change the sequence in which you get your opponents and still get powerful combos.
The only thing you have to bare in mind and it's important when engaging is to set fox-fire after you spirit rush towards your enemies(s) so those stupid fires don't go drifting away to an undesired target. The rest of the skills are quite intuitive, try to save you charm until you have a clear shot and keep spamming your orb as much as posibble to poke either in lane or in team fights.
Ok so you are vs an undesired mid, NO PROBLEM! Defense is the best defense. Stay behind your minions at all times, last hit meelee minions with auto-attacks and then push forward to get ranged minions with you orb hopefully getting the enemy champ in the way. With this start you'll keep your enemy at bay.
Remember, if your enemy hits you and you are out of pots, spam your fox-fire to get to 9 stacks and use your orb on a brand new minion wave to get healed instantly. Your passive along with the potions will keep you in-lane until your jungler gets to second blue, here you have 2 options, if your jungler is nice he'll give you blue buff keeping you in-lane for longer time, this is dangerous since (hopefully) you haven't gone back to base and the only tools you have are your boots and probably a pot or 2. So this is also situational if you think you can get a kill go ahead get blue and go get that annoying enemy afterwards go b for Giant's Belt and Sorc's shoes and probably even negatron cloak (that would be awesome). If you have low life get the blue back for Giant's belt and return to lane. Or if you don't get blue (mean Jungler!). Go back right when you hit six since you'll be running out of mana and enemy will soon make a move against you.
It's quite easy to lane with Ahri since it has awesome harass and easy last hits. You'll be surprised with the amount of damage you are dealing without having any AP items.
Of course you can kill an enemy before hitting level 6, but it's harder, after six it's just a breeze. the best attack sequence is at follows: Spam your orb as much as possible keeping in mind you'll need mana for the rest of your skills so try to stay above minimum for unleashing all your skills. When you hit the enemy with your orb (and getting around 1/3 or 1/4 of his or her health) activate spirit rush to land right beside your target, then activate Fox Fire, here he'll probably try to flee with flash or snaring/taunting/stuning you. After he tries to flee use spirit rush to catch up with him/her, when you caught up charm, ignite and hit him with orb and fox fire again. Doesn´t matter if you are under tower already since he'll be down in seconds and you'll still have one spirit rush left to make your grand escape. You can do this every time your spirit rush is up, it's quite easy to get kills with this strat. Remember try not to use spirit rush and flash at the same time in case you need to escape. This last thing is actually the most important thing when playing with Ahri. If you remember this you'll be unkillable.
That's it, I know this isn't the best guide ever, it doesn't even have images right? But this is your best option if you want to play Ahri no matter who you are laning against. Ahri is quite easy to master and in my opinion she is one of the most OP champs in the league and she should be banned as much as Morg or Shen in any ranked game. Used correctly and taking advantage of her great versatility you can take on any champ in mid lane. Any comments, suggestions or anything are welcome. If you liked this guide and want to improve it in any way let me know and I'll be happy to have your help. I just made this guide after winning 4 straight games w/o getting any deaths 7/0/14, 4/0/2, 11/0/13, 10/0/18 in ranked games. Playing against Ryze, Fizz twice, and Veigar. Don't be afraid of picking Ahri she can counter any champ in the league! Good Luck!