Luck

Luck is the statistic that determines a character's chance of being inflicted by a status inflicting problem attached to an ability used against you, such as Sleep and Stun.

It does not increase your own chance of inflicting said status effects onto opponents, contrary to common belief. Having a luck rating of 40 or higher provides immunity to Poison, Venom, Haunt, Death Curse, the target's HP being instantly reduced to 1, and being forced out of battle (Like the Djinni Gale's attack would otherwise have a chance of doing).

This means that any boss with a luck rating below 40 is in fact able to be affected by any of the above status conditions. All bosses in Golden Sun have luck ratings that would at least somewhat discourage trying to instant-kill them or afflict them with Venom, but with the exceptions of Saturos, the final encounters on top of Venus Lighthouse, and Deadbeard, it is otherwise quite possible to cause these effects to trigger on these bosses. Though in The Lost Age on the other hand, the only bosses that aren't immune to these status conditions are the Chestbeaters at the beginning, the Sea Fighter minions of the Briggs encounter, the Knight minions of the Moapa encounter, and the Ball minions of the Star Magician encounter.

Luck-related formulae
Any effect in the game that does not carry out with a flat success chance (like the innate 60%, 70%, and 90% chances of Quartz, Spark, and Dew, respectively) has its own base success chance that is lowered by the height of the target's Luck rating, and is also modified by the difference between the user's elemental level and that of the target, whether the target's element is its elemental vulnerability, and whether the target is a non-central target in a multi-target effect. The formula is as follows:


 * effect success chance = ((base effect chance + (25 if the target is vulnerable to the specific effect) + ((attacker's elemental level - defender's elemental level) - Floor(defender's luck / 2) * 3)) * (area multiplier))

The area multiplier in the above equation is .6 for when the affected enemy is one position away from the central target of a multi-target move like the Delude Psynergy, and .3 for when the affected enemy is two or more positions away.

The base chances for the effects in the game that are affected by the enemy's Luck rating are as follows:

Ways to increase Luck
Unlike your other statistics, Luck does not increase as you level up. Luck cannot be temporarily changed during battle, either. The only ways you can change an Adept's Luck are:
 * Using Lucky Pepper on the Adept.
 * Setting certain Djinn to an Adept.
 * Changing your Character class to one with a higher Luck rating.
 * Equipping luck-boosting equipment.