Luck in Demon’s Souls mainly affects item drop rate, plague resistance, and the Blueblood Sword’s damage; it does not raise the quality of drops, only how often enemies drop something.

Quick Scoop

  • Higher Luck means more frequent item drops from enemies.
  • It also boosts plague resistance.
  • The Blueblood Sword gets a special damage bonus from Luck.
  • It does not improve the rarity of a guaranteed drop, just the chance that a drop happens at all.

Extra Note

Some community sources mention very high Luck helping with rare-item rerolls or related item behavior, but the more consistent rule is that Luck increases drop frequency rather than drop quality.

Bottom line

If you’re farming materials or items, Luck is useful. If you’re hoping it makes rare drops “better,” that’s the part it doesn’t really do.