Mitsue Arihoshi is the grandmother of Bruno and the head of the Arihoshi family, a lineage renowned for its supernatural practices and deep historical ties to Yo-kai. A skilled sorceress from Sugoude, she wields the family's inherited power to draw magical stars in the air, using them for offensive strikes against Yo-kai or to conjure protective force-fields. Her expertise also encompasses technological invention, evidenced by her creation of a functional Yo-kai Radar designed to detect supernatural activity. In her youth, Mitsue had vibrant purple hair and wore a red-and-white hakama, a stark contrast to her current elderly appearance, which features grey hair, a wrinkled face, and a red, green, and black hakama paired with geta. She continues to wear shrine beads in her hair, a reflection of her spiritual heritage. Her demeanor is serious and knowledgeable, forged through years of dedicated study into Yo-kai and supernatural phenomena. She frequently shows frustration when her grandson Bruno disregards her guidance. Mitsue's childhood was defined by rigorous training in her family's traditions, which included active participation in Japanese holidays and honing her magical abilities at a shrine. She disapproved of her father's practice of mass-producing New Year's fortunes with stencils, favoring more authentic methods. During this period, she kept a pet dog named Nobushige, who was friends with a frog. A tragic accident occurred during a heavy snowstorm when Mitsue's magical powers misfired, toppling a lion dog statue onto Nobushige and the frog and killing them both. Her family concealed the truth to shield her emotions, leaving her to believe it was merely an accident. As an adult, Mitsue had a child who would become Bruno's parent. Following the death of Bruno's parents, she assumed responsibility for his upbringing and instructed him in the family's supernatural arts, ensuring he could master their inherited abilities. When the threat of the Onimaro invasion emerged, Mitsue identified the approaching meteor as an omen of impending doom and supplied Bruno with the Yo-kai Radar to track suspicious Yo-kai activity. She explained the Onimaro's nature as a virus-like Yo-kai species that infects humans through malevolent intent, resulting in chaos and destruction. In the Yo-kai Watch Shadowside anime, Mitsue meets Komasan and learns about his past as a dog, which mirrors her own experience with Nobushige. After a hole is found in the smaller grave where Nobushige's frog friend was buried, she grows nervous as others speculate about the statue's collapse. Yoshitsune uses his abilities to unveil the truth: Mitsue had accidentally caused the deaths due to her misfired magic. This revelation prompts Komasan and Komajiro to assume their Shadowside forms and assault her. Mitsue surrenders and offers an apology, accepting her unintended role in the tragedy and recognizing that her family had hidden the truth to spare her grief. Mitsue continues to lend her support to the Yo-kai Detective Agency with her extensive knowledge and inventive creations, regularly assisting in investigations and combat against supernatural threats.