Storm Shield

A warrior armed with a sword (including chainswords. power swords and force swords) can parry or turn aside an opponent' blow with his own blade. To represent thi a model armed with a sword can force an opponent to re-roll his highest attack dice before the winner of the combat is determined. Models armed with two swords can force their opponent to re-roll one or two of his attack dice.
The swordsman doesn't have to parry if he doesn't want to. Though parries are useful it is possible an opponent may re-roll and get a better score. An opponent who rolls several dice can always pick his next highest score and use that to determine who won the combat rather than use the score of his re-rolled dice. Re-rolled dice can still produce fumbles or critical hits as described below. Two opposing models which both have parries cancel each other out - neither can force a re-roll!