Kassar's Retribution is a Legendary flail for the Crusader in Diablo III. It requires character level 31 to drop. The unique affix grants movement speed when casting Justice. This effect does not stack with itself, but does stack with the Sword of Justice rune (and, in a manner of speaking, can replace it). Prior to Patch 2.1, it also granted Critical Hit Damage (that cannot normally roll on a weapon).