Ryouto Zygmunt is a tall, slim young adult with a height of 183 cm and a weight of 73 kg. His hair is gray or white, often slicked back and varying in length from short to hip-length or longer, featuring an ahoge and unusual eyebrows. His eyes are red, sometimes noted as pink and hososome in shape, set against pale skin that bears at least one scar.

He works as a spy and superhuman, skilled in martial arts. His typical attire consists of suits, neckties, and on occasion, a trench coat.

Ryouto Zygmunt appears as the protagonist in "Dyogrammaton" and "Clock Up Fan Disc 3GHz," and as a side character in "Zwei Worter" and "Clock Up Fan Disc 4GHz."