Like Ace, Gray Ringmarc works under Nightmare Gottschalk in the Alice in the Country of Hearts franchise.
Gray Ringmarc is created by Quin Rose and illustrated by Soumei Hoshino. His game role, the lizard, from Heart no Kuni game reflects Bill the Lizard's name (from Lewis Carrol's Alice in Wonderland novel). He has no information regarding any inspiration used to create him. He first appears in Alice in the Country of Hearts volume 4.
He appears when Alice arrives to visit Nightmare and Julius in the clock tower, and Gray is seen taking care of Nightmare who is ill at the moment.