You may think by now after reading the headline: "Ahri as ADC? Impossible. Just another troll-guide." but you're wrong.

First of all, what makes Ahri a good ADC?

- Ahri has a good range (550) which can easily keep up with common ADC's.
- She can taunt her enemies and force them to slowly walk towards her without attacking.
- Her passive is able to heal her for a certain amount.
- Her ultimate lets her chase down or escape enemies.

Which problems may occure and what are her weaknesses as ADC?

- Ahri has no escape chance until reaching level 6.
- Her heal is not always available.
- Being out of mana prevents her from taunting her enemies and makes her vulnerable.
- Difficult early game because her AD/lvl ratio is pretty low.

Ahri as ADC works best with any Supporter who has CC such as Leona, Alistar or Taric. Sona is a viable Support for her too concerning burst damage.

Note:
The skill order might not be correct. Just max your E first, followed by your Q and max W right after that.

Start with Boots of Speed, a health potion and two mana potions. Ahri's passive is able to heal her for a certain amount which means she has to use abilities. Thus you need more mana than health.

Your first item should be Sheen. It gives you Ability Powerand bonus damage on the next basic attack. Finish your Tri-Force as soons as possible.

Now that you have a certain amount of damage go on buying AS. I recommend taking Berserker's Greaves (upgraded to Alacrity boots for bonus movement after finishing Black Cleaver) and a Black Cleaver for AD as well as AS and Armor Penetration.

Finish your core items by spending your gold on a Bloodthirster which grants you Life Steal and a Last Whisper for more Armor Penetration.

Your last items depends on how endgame is going.
If you need more survivability consider a Banshee's Veil or Guardian Angel.
If you need more AD grab an Infinity Edge.
Does your team lack CC? Pick a Rylai's Crystal Scepter which makes you easier to hunt down your opponnents.

Ahri's power lays within her passive to heal herself and her taunt.

Playing her as ADC it is important to have a certain amount of base AP so your heal is strong enough to keep her in lane even with a support who isn't able to heal her such as Blitzcrank or Leona.

The second point is her taunt which makes her dangerous as Carry. But as soons as Ahri has no mana left she cannot pull her enemys anymore so pick Mana Regeneration runes to ensure you have your taunt ready if needed.

As for any ADC you should pick Attack Damage runes for marks and Health Quintessences.

Essential for Ahri as ADC is going deep into the Offense tree by taking every point that increases your damage output. Also take the point for Spellsword regarding your build containing some AP items too.
Movement and agility is important thus pick all 3 points of it in the Utility tree (Movement and Mana Regeneration) and spend 1 point on Lifesteal/Spellvamp.

People may hate on you playing a new meta game but League of Legends how we know it today only became like that because people like you and me tried new awesome things. So give AD Ahri a try and I bet you will be satisfied with the results.

As for any Carry your main goal is outfarming the enemy Carry. Ahri's movement and agility make her a dangerous enemy. Use it for your advantage but as with any other champ you need to play save to lead your team to victory.

I hope you will spread this idea and enjoy playing AD Ahri.