Runes are special alchemical items that heroes use to access new abilities activated automatically in combat. Runes can be studied as separate technologies at the fourth level of the Lyceum and are produced in the Laboratory. To build the Laboratory, you need to learn the "Alchemy" technology in the same Lyceum level.
A detailed description of each rune can be found in the "Information" tab by clicking on the "i" icon in the recipe card, as well as in the inventory by clicking on the rune or during the runing of one of the available weapons.
For more information about runes and their effects please refer to the guide on the game's website.