At the beginning of the story, Mikuni is depicted as an antique dealer with a childish nature and a passion for collecting dolls. However, behind that, Mikuni has a cunning, manipulative, and somewhat cruel nature. True to his surname, Mikuni was once part of the Arisuin family. He is the eldest son of the current Arisuin leader, and he is the older brother of Misono. Currently, Mikuni, along with Servamp of Envy, Doubt Doubt (Jeje), continues to monitor the movements of all Servamps and their Eve secretly while running his antique shop.