Rell Runes explained
There's one set of runes for Rell on patch 14.9 that is the clear favorite for LoL players and pros alike. The best Rell rune paths on the position 
Support are 
Resolve as the primary path and 
Inspiration as the secondary path with a pick rate of 71%. Besides picking runes on Rell you should learn how to play Rell and if you are interested in pro matches take a look on how a pro builds Rell. If you want to discuss 
Rell then you should visit the champion subreddit.
Rell runes from primary path
Resolve empowers the survivability of Rell and increases the tankiness. Most of high elo players – and our LoL pros in the the major regions – have agreed that 
Aftershock is the best keystone rune to run on Rell. This keystone rune bulks you up, increasing both armour and magic resistance, once you immobilized a champion. Aftershock synergises both with the sheer amount of crowd control Rell possesses and the need to be tanky as soon as you engage. Other primary runes on Rell are 
Font of Life, 
Bone Plating and 
Unflinching.
Font of Life provides your teammates with more sustain by healing them whenever they attack a champion whose movement you've recently impaired. Bone Plating make Rell overall tankier, by decreasing the amount of poke damage in the early game. Unflinching inceases Rell tenacity based on your missing health.
Rell runes from secondary path
When it comes to your secondary path, most Rell players prefer to go with Inspiration. Inspiration opens creative opportunities on Rell troughout the match. On the Inspiration path, the best runes for Rell are 
Hextech Flashtraption and 
Cosmic Insight.
Having an extra way to decrease the distance with the Hextech Flashtraption will make an engage much easier to pull off. Cosmic Insight grants summoner spell and item haste.
FAQ for Rell Runes
Which is the best keystone rune on Rell?
The best keystone rune on Rell is Aftershock. This Rell runes setup is then referred as Rell Aftershock.
What runes does Rell use?
Runes from the paths Resolve and Inspiration are the most used runes on Rell. For the exact pick rates of Rell runes used, you have to study the rune distribution presented.