It turns out that Keiji Inafune's new "Yaiba" game that was last week is actually the name of the lead character of the actual game, Ninja Gaiden Z, and while Yaiba is dealing with zombies, he's after the iconic Tecmo ninja himself, Ryu Hayabusa.
According to Inafune, "The collaboration I'm announcing today is almost like a dream come true. The reality, for a lot of creators, is that they can't make the games that they really want to make. There are boundaries and rules and people that have some say. I'm very happy that I'm here today being able to make the games that I really want to make."
There was no release date given for Ninja Gaiden Z, and that it would only be released for unspecified consoles, which likely are the PlayStation 3, Xbox 360 and Wii U.