Ninja Gaiden Sigma, like the original, stars the young Dragon ninja Ryu Hayabusa as he fights against the Black Spider Ninja Clan to save his village. He is lent the legendary Dragon Sword by his father before the start of the game. The Sigma edition includes extra missions with Rachel (a Fiend hunter from the Holy Vigoor Empire who is in possession of the “Fiend’s Blood” curse), and a new Mission Mode that does not affect the overall plot.