Gurio Umino, usually called by his family name "Umino", is a socially-awkward friend of Usagi Tsukino and her best friend Naru Osaka. He is very intelligent , but at some point, he could be arrogant and a bit of a "Mr. Know It All".

He was usually the one who kept the others up-to-date on information on Sailor V, the strange crimes and rumors in Tokyo, and on students such as Ami Mizuno and Makoto Kino.