Potions: Used to grant experience to your heroes in order to increase their level. Potions are earned by clearing stages, as quest rewards, and can be found in the store.
Scrolls: Used to level up the skills of your heroes. Scrolls can be found in the Tower mode and the store.
Runes: Used to raise the Rune Rank of your heroes. Whenever Runes are equipped to your heroes they provide a boost to that hero's stats. Runes can be found by clearing stages and in the store.