The Luck effect is what modifies the amount of luck points the player has. Luck is used for critical hits. The higher your luck points, the higher the chance of you performing a critical hit. When a negative version (nerf) of this effect is applied, the player will have decreased luck points, and then less chance of critical hits. When a positive version (buff) of this effect is applied, the player will be given additional luck points, and thus more chance of getting critical hits.