Move Silently

​A thief can try to move silently at any time simply by announcing that he intends to do so. While moving silently, the thief's movement rate is reduced to 1/3 normal. The DM rolls percentile dice to determine whether the thief is moving silently; the thief always thinks he is being quiet. Successful silent movement improves the thief's chance to surprise a victim, avoid discovery, or move into position to stab an enemy in the back. Obviously, a thief moving silently but in plain view of his enemies is wasting his time. ​