Dantro, The Planet Man was an agent of the League of Planets who upholds peace and fair play. Like all agents of the League, he is forbidden to resort to violence, except in self defense. However, he is a skilled fighter, and he carries a sidearm at all times. He is a humanoid from Planeris Rex, and he was the first representative of the League to make contact with the humans of earth. He still has much to learn about human customs and sayings. He went on to save the solar system from the evil of Marston of Mars, and later had adventures beyond the solar system.