Team Ninja have big plans for post-launch content in Ninja Gaiden 3; Siliconera is reporting that new characters, missions and challenges will be among the DLC offerings for the game.
Gaiden 3 will have a sweep of online modes including co-op and competitive. It’s likely that DLC will correspond to said modes instead of single-player stuff, although maybe the challenges will require a solo effort.
As for characters, any guesses? Rachel is likely to show up, other than that we’re stumped.