The Sword of the Mighty Warrior is the secnd sword the Prince gets in The Sands of Time. It is found upon a pedestal that sits above the baths of the Palace of Azad, and it allows the Prince to break cracked walls in three hits. You can also see this sword on the ship in Warrior Within; its user is the crew member who charged Shahdee.
http://princeofpersia.wikia.com/wiki/Sword_of_the_Mighty_Warrior