The best part about Ninja Gaiden games with the word "Sigma" after them is the chick gameplay.

Never can a girl feel so objectified or empowered as when watching a ninja in a bright pink obi bow or a torture corset take down hordes of blood-spurting enemies. Get a look at these two Ayane gameplay vids to see what I'm talking about.

Aside from Ayane, we're also getting Momiji from the DS game, Ninja Gaiden: Dragon Sword and Rachel may or may not still be a playable character either in the game's story mode or online co-op mode.