Runes are something that is going to play a nice role in shaping our builds into something more. It will function as a support roles allowing us to passively boost our skills, properties and even allow us to boost our stats by a good margin. Keep in mind, as you progress set tiers you will end up needing a lot of them and they do tend to get pricey in the grand scheme of things.
You can find runes dropping from most of your Ancient Bosses and Elite Monsters but you can also grab them from the Garnet Shop as well as the Reputation Shop.
During limited events such as the Saturday Double Exp event you can also pick up a Purple Rune for your accesories through one of the packages.
Every rune you equip has it's own stats and benefits but there is one thing that seperates these different types apart!
Blue Runes: Can not be upgraded comes with lower stats.
Green Runes: Can not be upgraded comes with slightly better stats.
Purple Runes: Can be upgraded, comes with the best rune stats and you can socket Rune Skill Shards into them.
Rune skill shards are designed to help boost our skills or properties while attached to our Purple Runes. Now some of these are better than others and come in all varieties with you receiving the best benefits from your red or Legendary Skill Shards