Xarthab was the son of the previous ruler of the Grundos, but argued with his brother, Zorlix. Eventually, the two split into two factions of Grundos, with Xarthab taking the oranges. The war was helped by Dr. Sloth, but eventually the two brothers teamed up to help defeat Sloth.
Listen up, recruit! I'm not letting you near a real spaceship until you prove that you can handle the dangers of space! I bet our slowest soldier could beat you with his antennae tied behind his back. Think you can show me otherwise?