Misako Mishima is the aunt of Touko and Rinko Mishima from their father's side. She is 29 years old and serves a crucial role as the shrine maiden who unseals the Dream Cyclone weapon whenever the Yume Tsukai are called into action. She resides at the family house where the Dream Cyclone shrine is located, remaining on standby for when the team requires her assistance.

In terms of personality, Misako is notably sensitive about her age and makes a point of insisting she is 29, not 30. She keeps up with modern technology but deliberately limits her use to a cellphone and computer, suggesting a pragmatic and controlled approach to the digital world. While she is a supporting figure rather than a frontline fighter, she is also described as an amateur dream-user, possessing the innate ability to exterminate and control nightmares alongside her niece Touko. Her primary motivation is to aid the Mishima sisters in their work, waiting dutifully to provide the means to harness the Dream Cyclone against escaped nightmares.

Misako’s key relationships center on her nieces, Touko and Rinko, whom she supports from the family home. Her role is largely static rather than undergoing significant development throughout the story; she remains a steady, background presence who supplies the necessary weaponry and maintains the shrine. Her notable abilities include the ritual of unsealing the Dream Cyclone, as well as the general powers of a Yume Tsukai to sense, engage, and pacify nightmares. She is depicted as a dedicated and dependable figure, albeit one with a minor vanity about her age.