Full Name: Xeno Houston Wingfield. American, born October 1, 1993. He is currently 11 years old and attending university(?). His experiments are quite sophisticated and dangerous for his age. His way of speaking is very mature. When he likes something, he uses the exclamation "Elegant." He calls Stanley "Stan," likely because they have been close since they were very young. He loves cheeseburgers. In fact, he is clumsy at everything except science. He only started eating cheeseburgers because Stanley suggested it, and Stanley is his only friend. He is cute. There is a bit of a height difference between him and Stanley.

Full Name: Stanley Snyder. American, born September 1, 1993. He is currently 11 years old. He is a normal(?) elementary schooler. He seems to love candy, as he always has a lollipop in his pocket. He is Xeno's only friend and sticks close to his side. He doesn't particularly like it when Xeno talks about science and has no intention of listening closely, but he listens anyway. He just doesn't know scientific principles; he is by no means stupid. It's just that Xeno is too smart. Additionally, Stanley's parents are soldiers, so he has been around guns since he was little. He seems to have set his career path toward the military. On the other hand, his parents are quite strict (for example, he can only play video games when a friend visits, or he gets in trouble if his test scores fall below a D). However, this strictness has actually made Stanley more of a brat. He loves burritos.