Bad Luck represents a character’s negative accordance with The Pattern. With Bad Luck, the character generates a series of happenstances leading to a bad outcomes. The point is not to kill the character, but to make them suffer from their ill fortune.
More reflective of the Good Luck and Bad Luck represented in Bane and Bless, Bad Luck imposes a penalty of -4 to every attack and saving throw or any ability check for a single round, or a single use of Disadvantage. The use of which is decided upon by the GM. One instance per Long Rest is imposed on the character.