For the Thief Job Change Guide, see here.
Besides the Platinum Skill Quests, the Thief class also can do a training quest, which gives them Base and Job EXP and a Mantle.
|Detoxify||Remove the Poisoned status from a targeted character||1||Supportive|
|Double Attack||Increase the chance of performing double attacks when using Dagger Class Weapons. This skill also affects Left-Hand damage with Katar Class Weapons.||10||Passive|
|Envenom||Cause Poison property damage to a target with an attack which has a chance of also inflicting the enemy with the Poisoned status.||10||Offensive|
|Hiding||Hide under the ground to avoid enemy attack. Detection skills will cancel Hide status.||10||Active|
|Improve Dodge||Increase Flee Rate. Flee Rate increases based on your job class.||10||Passive|
|Steal||Steals items from monsters.||10||Active|
|Back Slide||Quickly move backwards to position yourself safely away from threats.||Active||Back Slide Quest|
|Pick Stone||Pick up a Stone from the ground.||Active||Pick Stone Quest|
|Sprinkle Sand||Kick sand into the face of an enemy which will inflict 130% of the damage of a normal attack and also have the chance to cause the Blind or Stun status on the target.||Offensive||Sprinkle Sand Quest|
|Throw Stone||Attack an enemy with a Stone which inflicts 50 damage that will pierce enemy defense and has a low chance of causing the Stun or Blind status.||Offensive||Throw Stone Quest|