Misako Shimizu is a 25-year-old office worker and colleague of Yuu Arahama. She possesses striking violet eyes and long violet hair, typically styled with a side part and sometimes tied in a side tail. Her young-adult physique features noticeable tanlines. She consistently wears office-appropriate attire like blouses, skirts, and pantyhose, often accessorized with a choker or necklace; variant outfits include a naked apron and torn pantyhose in specific contexts.

Her relationship with Yuu began after accepting his invitation to eat, leading to their first sexual encounter where she lost her virginity to him. Developing romantic feelings, she mistakenly believed their relationship was exclusive and progressing toward marriage. This culminated in her proposing to Yuu following an intimate moment, only for him to reject her. Yuu clarified he saw her solely as a sex friend and revealed his four other concurrent partners: Ryouko Yanagi, Kotori Hoshino, Makiko Endou, and Aina Kamishima.

Enraged by Yuu's rejection and deception, Misako contacted the other women and demanded they gather at Yuu's apartment for a confrontation. There, she insisted Yuu end his casual relationships and commit to marriage. The situation escalated dramatically when all five women discovered Yuu had individually proposed marriage to each of them. Consequently, Misako joined the others in a competition to become Yuu's chosen bride. Her sexual preferences include gentle intercourse and creampies.