He is voiced by the late Tomoko Kawakami and Hoko Kuwashima in the Japanese version of the anime, and by Leah Clark in the English version of the anime.
He is a stereotypical nerd 12 year old on the surface, Fuyuki is an oddity even within that scope, as his main interest is in the 'occult' - a term that comprises everything from the best known international mysteries (Stonehenge, the Bermuda Triangle, ghosts, UFOs, etc.) to the obscure, like the Seven School Mysteries (a grab-all term for haunted schoolhouses). A dedicated explorer and adventurer, Fuyuki sadly lacks the athletic skills required. Swimming in particular is a huge handicap for him, specially in contrast with his athletic older sister Natsumi. However, in the rare opportunities Fuyuki gets mad, it is enough to scare both Keroro and even Natsumi into submission. Despite his fascination with the paranormal, he does not have any spiritual sensibility, in contrast with his sister. He is scared of bugs. However, he is a master teller of horror stories. Also his best friend is sgt keroro and was the one who discovered his exsistance while his sister was waking him up. Though his sister Natsumi was the one who pointed to his hiding spot he is the one who saw the paper peeling first and while staring he captured Natsumi`s attention and she also saw Keroro.
Fuyuki's Keronian partner is Keroro, even though Keroro is supposed to be his enemy. The two do share a natural curiosity (Fuyuki is drawn towards the mysteries of the world, while Keroro is mystified by things most humans consider commonplace), as well as the strongest friendship of the five Keronian/human child pairs. He affectionately calls him 'gunso' or 'gunso-san', meaning 'sergeant'. His appeals to their shared friendship are enough to stop Keroro's plans more than once. Fuyuki is delighted by all the wonders he gets to see with the keronians and jumps feet first in many of their plans.
He created an occult club in his high school, of which only he, Momoka, and Chiruyo are the only members. However, he seems unaware of either Momoka or Chiruyo's crushes on him. He possibly has feelings for Alisa Southerncross.