Yokomizo Sango was originally the head inspector of the Saitama district, though he transferred to the Shizuoka district soon after. However, he and his twin brother Juugo, who is also a police inspector and has remained in Saitama, stay in touch and have even assisted each other in various (and even locally unrelated) cases.

Yokomizo is a capable police officer, though with one odious personal habit: he tends to get his face right into a suspect's face, study them closely, and scream into their face when he believes he is onto something, a habit which even he believes is a little embarrassing. Another trait of his is to speak really loudly when deeply involved in an investigation. His loud voice has received many complaints from suspects.