[Source] The Shard of Retaliation was an object that had been imbued with a powerful measure of the Force. When it was activated, it allowed the holder (or a group of) to retaliate against all incoming attacks while they kept their mind focused. This effect was devastating in combat, as it allowed the holder to block any melee strikes and deflect any ranged attacks. However, this effect only lasted for short amounts of time before the shard had to be reactivated.