Xenos is the brother of Xerxes von Dux 3348 and Xoras 4303 who also got stolen away from their home. Unlike his brother, Xerxes, Xenos grew up to be vicious and rose up to the ranks of "top dog". After defeated by a new contender, Xenos got thrown away and was up for euthanasia when a man named Richard decided to adopt him as a gift to his second son, Jirou. At first, Jirou did not want to have any part that has to do with him but as the days passed by the pair became the inseparable ones. Xenos matured and with Jirou's care gradually became less snappy, only doing so when ordered to or when threats come and attempts to harm Jirou. He is unyielding to anyone but very loyal to his little Jiji. He is currently mated to Sarabi 3693 and is very protective of her. She's the one who melted his icy heart.