Ahri Runes explained
There's one set of runes for Ahri on patch 15.9 that is the clear favorite for LoL players and pros alike. The best Ahri rune paths on the position 
Mid are 
Domination as the primary path and 
Sorcery as the secondary path with a pick rate of 43%. Besides picking runes on Ahri you should learn how to play Ahri and if you are interested in pro matches take a look on how a pro builds Ahri. If you want to discuss 
Ahri then you should visit the champion subreddit.
Ahri runes from primary path
Domination improves burst damage and assassination tools on Ahri. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Electrocute is the best keystone rune to run on Ahri. This keystone rune provides burst damage, aiding them in nuking down the enemy carries. Other primary runes on Ahri are 
Taste of Blood, 
Grisly Mementos and 
Ultimate Hunter.
Taste of Blood heals Ahri as soon as you damage an opposing champion. Ultimate Hunter scales up Ahri ultimate haste on every unique champion takedown.
Ahri runes from secondary path
When it comes to your secondary path, most Ahri players prefer to go with Sorcery. Sorcery empoweres abilities of Ahri and increases the available champion resources. On the Sorcery path, the best runes for Ahri are 
Manaflow Band and 
Scorch.
This is usually followed up by taking Manaflow Band for additional mana and mana regenaration. Scorch increases your control in the early game.
FAQ for Ahri Runes
Which is the best keystone rune on Ahri?
The best keystone rune on Ahri is Electrocute. This Ahri runes setup is then referred as Ahri Electrocute.
What runes does Ahri use?
Runes from the paths Domination and Sorcery are the most used runes on Ahri. For the exact pick rates of Ahri runes used, you have to study the rune distribution presented.