Niddle is a Gnoll and the best Finagler in the world. He is currently Finagling Camora and Comshaw. His blond hair has an uncanny resemblance to Mortimer's. He is somewhat oblivious, appearently dependent on others and a little naive.
Niddle has picked up a crystal here. So far, we do not know what it is and how it effects him, if at all.
His first appearance is here, the leftmost gnoll in the fourth panel.