 Subtracto is a Nomad Artificer, a race of machine-intelligences predating the universe, although he seems to believe that he is a mere Artificer construct.Found in the Astral Rifts by Empress Lynn of Shangri-La, he befriended and helped her get back to Earth.After a reformed Madrid was rescued and brought to Shangri-La to recover, he befriended her as well, and now explores the Astral Rifts with her.