Runewords are available from some merchants, but components can also be found by exploring or battling creatures.
Crafting/Upgrade: A runeword can be inscribed onto a piece of magical or better equipment to grant additional bonuses to related active feats. Only one runeword per piece of equipment, an existing runeword can be replaced with a different one. Applying a runeword to a piece of equipment will not increase the required level of use.