To get Runes, Diablo 4 players must have the Vessel of Hatred DLC and progress through the main storyline to unlock the system first.

Runewords, and not “Rude words” like you thought, are a new mechanic in Diablo IV: Vessel of Hatred, letting you add new customizable, conditional buffs to your equipment. These socketable items can be dropped by enemies and chests across Diablo IV—here’s how to find them and use them.

Diablo 4's common materials are not common at all in Vessel of Hatred and it can act like a brick wall for progress.