One of the main stats in the Shadow Hearts series. Luck usually affects things such as critical hits and finding rare items after battle, but also can influence other stats like Evasion and Accuracy.
Various abilities and equipment can alter the Luck stat. Also the notable abilities of Lucia's Aromatherapy, Tarot Cards and Ricardo's Serenata can temporary effect a character's Luck. Luck can be increased between 1-5 points by using the Seal of Luck item, though the bonus added varies between games.