Thieves are adventurers who make their living by their agility and cunning. This has ensured that their reputation as heroes is always challenged; however, many thieves do indeed use their skills (mostly) in the defense of the common good. Nevertheless, it does not pay to relax one's guard when near anyone with as much stealth as a thief possesses.
Having a thief in the party increases the chances of striking enemies first and decreases the chance of being ambushed. The thief's quickness often allows him to strike the first blow in a battle. However, the thief is not able to cast any spells and cannot use most of the stronger equipment.
The Thief upgrades to the Ninja. Despite the Thief's weakness early on, the Ninja is possibly the best upgrade of the six character classes.
Thieves depend mainly on Luck to get them through battles. They are average in most of their other statistics, with a minor boost in Agility.