Yomi is a young boy who wears a helmet on his head. He has chin-length hair which covers most of his forehead.
Yomi is generally quiet and is often not seen speaking. He acts in a professional and composed manner, and has shown to be quite analytical. He is known to be extremely intelligent and skilled at creating trion technology.
- As with the other Galopoula Expedition Force members, Yomi's name originates from a character from Kiteretsu Daihyakka, with some possible modifications. In his case, his name comes from the character Miyoko Nonohana's name (野々花 みよ子).
- According to Volume 16, he likes;
- Hot milk with plenty of sugar
- Trion engineering