Runes are special items that allow the player to 'enchant' different weapons, tools and armor with different effects. They can be dropped by monsters and bosses.
Runes can be divided into several levels, From 1 to 7. Each level costs 4 runes of the same type from the previous level, resulting in a total of 4,096 level 1 runes to merge a level 7 rune of that type.
If enchanting weapons or tools, the 'Atk' stat will be chosen. If enchanting armor the 'DeF' stat will be chosen.
Runes will usually also negatively impact health when enchanted to armor pieces.