Mikako Satsukitane is a student at Sorami Academy where she serves as the president of the student council, making her an upperclassman to Tomoki Sakurai and Sohara Mitsuki. She is the only daughter and heiress of a powerful yakuza family that manages the town of Sorami, and she is the childhood friend of Eishirou Sugata, whom she addresses as Ei-kun. Mikako is characterized by her manipulative and cunning nature, combined with a high level of intelligence and a pronounced sadistic streak, which she often directs toward Tomoki. She frequently torments him for her own amusement, and her demeanor is typically marked by a constant, knowing grin. Despite her role as a student leader, she is noted to have failed in morals, necessitating supplementary lessons. In combat, Mikako demonstrates exceptional physical abilities, including a grip strength of four hundred kilograms, shown when she lifts Sugata with one hand and knocks him out during a wrestling match. She also displays proficiency with firearms, though this is seen within dream sequences. Her motivations are largely self-serving; she treats Tomoki well at times but primarily uses him as a source of entertainment to relieve boredom or anger. In the story, Mikako remains a recurring figure among Tomoki's circle, using her position and skills to influence events around her, while her relationship with Sugata is marked by a competitive dynamic rooted in their shared history.