Cursed Luck has a 50% chance to add a negative drn to the bearer's Defence and Protection rolls. Why is it all lowercase? Because, fortunately for the bearer, only one six-sided die is used as the base for this effect; regular DRNs use two.

Cursed Luck can, in fact, bring a fellow below the traditional minimum result for rolling a DRN (or even a regular 2d6). It cannot make the result negative, however; the minimum is zero.

Even with only a 2-point change in the floor, Cursed Luck massively increases the likelihood of being critically hit, which requires a 2 or lower for the DRN result. Out of 1296 Cursed Luck DRNs, around 490 will be 2 or lower, around 625 will be 3 or lower, and around 758 will be 4 or lower. For 1296 regular DRNs, 36 will be 2's, 108 will be 3 or lower, and 216 will be 4 or lower. Thus:

• Against most units with Cursed Luck, around 20.29% of all hits (~13/64) will be armor-defeating.
• Against units with Cursed Luck and 50-99 Fatigue, around 28.29% of all hits (~9/32) will be armor-defeating.
• Against helpless/entrapped units with Cursed Luck, around 37.58% of all hits (~3/8) will be armor-defeating.

The average result of a DRN is an 8. The average result of a Cursed Luck DRN is around 4.25, so Cursed Luck effectively:

• Reduces Defense Skill for melee attacks, and possibly the Shield Parry in missile combat, by an average of 1.875
• Increases Armor-Negating Damage on them by an average of 1.875
  • Due to critical hits, this increase is higher for hits that respect Protection, though never enough to out-scale Protection.
  • For a person with 10 max HP, this also means each AN hit is around 18.75% more likely to cause an Affliction!

Does the effect apply to anything else? Perhaps. The public information on this is two games out-of-date.

Fateweaving is the most common source of this thing; attackers of Fateweavers, if their attempts aren't stopped by Petrification, Awe, or Vine Shield shenanigans, have their Luck cursed if they fail a Magic Resistance check versus the indicated value.

Cursed Luck negates Luck! Luck gives a fallback 75% chance to not take damage from hits that would kill, as long as they aren't instakills. Cursed Luck shuts this lifesaving ability off completely.