Sharing the same circumstances, these two are a community of fate whose existence is a source of mutual emotional support. Their deep bond of trust, allowing them to understand each other without words, is the driving force behind solving numerous difficult cases. Especially in tense situations involving the Black Organization, their cooperation can be described as being of one mind.

As high school detectives from the East and West, they are the best of rivals and, at the same time, the best of friends. They acknowledge each other's reasoning skills and, while sometimes competing, do not hesitate to cooperate to solve cases. This exquisite distance between them makes their relationship all the more fascinating.

Akai's figure, appearing gallantly in Ran's moments of crisis, is exactly that of a knight protecting a princess. Perhaps Akai sees in Ran the image of a woman he once loved. Although they have few direct points of contact, Akai's presence watching over Ran from the shadows adds depth to the story.