What good is a shield? Why, to stop things from hitting you, of course. Shield Block does this automatically (once practiced). If a blow is deflected by Shield Block, it does no damage. A high dexterity helps in getting the shield into position to block. Also, chances are partially level-dependant: the lower the mob's level (or the higher your level), the better chance you have of deflecting the shot. Some shields contain magic spells which will discharge against the attacker after a successful shield block.
Syntax: none (automatic).