A researcher in the Lab Team of Xio Japan's R&D section and a special Xio officer. Despite being a researcher, he is a curious man of action who participates in actual combat. He is a kind-hearted character who wishes to coexist with monsters rather than just destroying them, even while fighting on the front lines.

A 19-year-old female officer serving as Daichi's bodyguard. Although she is the youngest member of the Xio team, she has a very strong personality. She has a major complex about her image as a 'strongwoman' because of a past experience where she made her first love cry by fighting him seriously in a kendo match during childhood.

An officer who can be rough in manner and clumsy in interpersonal relationships but has a strong sense of justice. He is a master marksman and a top-tier driver of special vehicles. He was a rugby player in high school and was scouted by Xio for his outstanding athletic nerves. Having the best space adaptation training results, he was selected as the pilot for the Space Musketty.

A pilot who operates the fighter-type special mecha Sky Musketty with incredible technique. He acknowledges his enlistment peer Wataru but often clashes with him as a rival.

A genius girl who always showcases unique fashion. A returnee who dabbled in various inventions while studying abroad, she is the mood maker of Xio, softening the atmosphere with her innocent words and actions. She seems to be very fond of Eleking.

The Captain who leads Xio Japan. He holds a strong conviction that one must understand the enemy rather than just defeating them. Even facing the reality of having to fight monsters that threaten humanity, he never gives up on understanding and coexistence.

The Deputy Captain of Xio Japan, in charge of information analysis and strategic planning. A former Hyper Life Rescue member, she shows a strict yet caring side, such as scolding Asuna for wearing heels during an operation but later buying her a new pair of shoes.

A young genius scientist on the Lab Team. A relaxed and kind man, he rarely loses his composure. He hits it off well with Daichi, as they conduct research in overlapping areas of expertise.

The one in charge of Xio's weaponry and mechanics. Thanks to his superior scientific prowess, Xio's technology has become top-class among historical defense forces. He has a large appetite. He once showed his side as a gag character by drinking a transparency liquid invented by Rui and denying it, only to be shocked when the effect kicked in 7 hours later.

An Ultraman of unknown origin. He projects his data onto the transformation device, the X Deviser, and materializes by 'Uniting'—integrating his being—with Daichi Ozora.