|First Appearance||Ben 10: Secret of the Omnitrix|
Xenon is one of the darkest and most feared planets in the galaxy and has earned the reputation of being the destination of no return, as proven by the thousands of shipwrecks left by those who try to navigate through the asteroids and perpetual darkness.
Azmuth chose Xenon as a way to escape the "mayhem" of the rest of the universe and to be able to continue his work in peace. He and Myaxx created a device that absorbs all the light in the vicinity, thus creating perpetual darkness around Xenon. That, combined with the large asteroids surrounding Xenon, force ships, who attempt to come close, to crash blindly into the asteroids. Azmuth created a homing beacon in the Omnitrix so that if it is ever in range, the Omnitrix will lead the user through the dark oblivion to get to Xenon.
- Ben 10: Secret of the Omnitrix (first appearance)
Xenon's name is a spoof on the fictional planet Krypton (Superman's home-planet), which similarly shares its name with a noble gas.