The Thief is a character class in the Final Fantasy and Fire Emblem series. They specialize in agility and evasion, and, as their name suggests, stealing from enemies.
Thieves appear as early as the first game and generally equip knives or daggers, have high speed and agility, and have low strength and defense. Ironically, in the first game, thieves can not actually steal from enemies. They usually appear in green clothes and wear a bandana on their head. Their skills include being able to flee from battle faster, stealing items or gold from enemies in battle, and using an ability called "Mug" that allows them to attack while stealing.
Thieves have similar stats to the Final Fantasy series, but, until Fire Emblem: Path of Radiance, they equip swords. They are able to equip knives in later games. Thieves' skills include stealing unequipped items from adjacent enemies, opening doors and chests with lockpicks, and being able to see far distances in the fog of war.