When he tries to fight him, the Dark Prince mimics his every movement. The Dark Prince attempted to kill the Prince, but the Prince dodged his attack and rushed him. The Prince collided with the Dark Prince and the shadow disappeared, allowing him passage into Jaffar’s room.
Because the Dark Prince is a mirror image of the Prince, the player cannot beat him in melee combat. The Dark Prince can move faster than the Prince, and will attack with a wide sweep of his sword.
Dodge the attack, and walk directly into the Dark Prince. The Dark Prince will disappear, allowing the player to progress to the next level.