Microsoft's PlayXBLA noted the renewal, saying the company's legal department authorized the following statement about the franchise: "We have either renewed or refiled a trademark application in various jurisdictions."
The takeaway here is not much more than Microsoft protecting its rights. The most recent mention of the series was an interview with a former 3D modeler at Rare, who said, "We all wanted to make KI3, but Microsoft [was] more interested in broadening their demographic than making another fighting game ... So it never got made, I doubt it ever will."
[Thanks to all who sent this in.]