Professor James Grey was a engineer and ichthyologist, and short-term member of the League.
During his boyhood, James Grey was a survivor of the 1898 Martian invasion, in which his parents were killed. He was saved from the same attack by Captain Nemo and traveled aboard the Nautilus. These events inspired Grey to become interested in marine studies and subsequently build his own submarine, the Iron Fish, which modeled itself after a swordfish.
In 1946, Grey was recruited by MI5 to the League and acted as a surrogate of Captain Nemo. The League did not last long and Grey soon left following its breakup. As of 1949, Grey was assume lost at sea according to a newspaper clipping.
James Grey appears in The Beano comics.