Ninja Gaiden on nes Game

Ryu Hayabusa of the Dragon Ninja Clan finds a letter from his father, Ken Hayabusa, explaining that he was leaving for a duel with some unknown warrior. The letter claimed that, should he not return, Ryu was to take the Dragon Sword, a mystical weapon and family heirloom said to have grown from the fang of a dragon, to America, where he should seek out a man named Walter Smith. In Europe, this title is known as Shadow Warrior.