Mel Runes explained
There's one set of runes for Mel on patch 15.9 that is the clear favorite for LoL players and pros alike. The best Mel rune paths on the position 
Mid are 
Sorcery as the primary path and 
Precision as the secondary path with a pick rate of 93%. Besides picking runes on Mel you should learn how to play Mel and if you are interested in pro matches take a look on how a pro builds Mel.
Mel runes from primary path
Sorcery empoweres abilities of Mel and increases the available champion resources. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Arcane Comet is the best keystone rune to run on 
Mel. This keystone rune adds more damage to your abilities and increases your power in the laning phase. Other primary runes on Mel are 
Manaflow Band, 
Transcendence and 
Scorch.
This is usually followed up by taking Manaflow Band for additional mana and mana regenaration. Transcendence for some more Ability Haste. Scorch increases your control in the early game.
Mel runes from secondary path
When it comes to your secondary path, most Mel players prefer to go with Precision. Precision improves attack and sustained damage on Mel troughout the match. On the Precision path, the best runes for Mel are 
Presence of Mind and 
Cut Down.
Presence of Mind helps Mel with the mana problems by restoring missing mana, if a champion is killed. If the enemy team consists of multiple tanks, then the rune Cut Down is the best choice.
FAQ for Mel Runes
Which is the best keystone rune on Mel?
The best keystone rune on Mel is Arcane Comet. This Mel runes setup is then referred as Mel Arcane Comet.
What runes does Mel use?
Runes from the paths Sorcery and Precision are the most used runes on Mel. For the exact pick rates of Mel runes used, you have to study the rune distribution presented.