Xen is an immensily strong saiyan stuck in this form. He was mutated by a deranged scientist, named Dr. Nico. He traveled the universe to find strong opponents to defeat. After he defeated the planets strongest warrior, he would take their powers, making them his own, then he would destroy the planet. He then eventually found Earth, and attacked. He defeated all the Z-Fighters, in a matter of minutes. They had to call Goku to help them defeat Xen. Goku and Xen had a epic battle that went down in saiyan histroy. Xen then poweered up to his max and defeated Goku. He was about to take his powers, when Vegeta used Instant Transmission and teleported them all away. Then the 2 saiyans fused into Gogeta and defeated Xen by launching into space with a Big Bang Kamehameha x100. Little did they know that he had a regeneration ability that kept him alive. He then crashed on a inhabited planet and there he healed. He trained on the planet for decades waiting for the best moment to take revenge.
Xen is very powerful, so powerful infact he took down all the saiyan Z-Fighters in minutes while they were in SSJ4 form. He also had absorbed a lot of powers boosting his power dramatically.
Xen has golden fur covering his torso and arms. His hair is a mixture of white, green, and brown. He also wears earring similar to Pottara Earrings. Xen has a red belt, green pants, black and green boots, black and green bracers, and has red eyes.