(Problem) What piece?

Feb 3, 2014, 11:57 PM |

In the following diagram, there is an unknown piece/color on h2 (here labelled as a Black knight just because Chess.com doesn't support other markers). What is that piece so that the position is legal?

The original post is here, post #418. Since I believe this is a good problem that I created, I also cross-post it here, so I can keep track of my good problems. :P