Four more characters, Ayane, Rachel, Momiji, and Kasumi, are available in addition to Ryu Hayabusa. With your chosen characters, you may form a tag team and easily switch the playing character during combat.

Guides
Ninja Gaiden Σ – How to Unlock All Costumes (Ninja Gaiden: Master Collection)
Guide to unlocking all the costumes in the Ninja Gaiden Collection. All Costumes Guide Shinobi Shozoku The purple Shinobi Shozoku is available for Ryu at the start of the game, […]