Dr. Filius is a scientist operating out of a Submarine located in the center of a planetoid in the Netherworld. He was not native to that universe, but was somehow trapped there. He later joined Chris DeLuca aboard the Featherpool Ship. Before meeting Chris, he survived in the Netherverse by living in a submarine of his own invention in the liquid center of the First Planetoid. He also conducted physics experiments on the world around him.