General attributes influence all characters' classes and how they interact with objects and other people in the game; high values in strength allows movement of heavier objects and communication helps with bargaining goods with sellers. These attributes are changed by performing actions related to the skill; climbing a tree eventually increases the skill value in climb, running increases vitality, and so on. There are also complementing skills which are tied to specific classes; parry (the ability to block a blow with the sword), for instance, is mainly used by fighters and paladins, lock picking and sneaking are defaults with the thief, and the ability to cast magic spells is usually associated with magic user.