Mirai is a white witch of the Wicca Institute where she was an acquaintance of Hinoe Shinozaki. She has a strong connection with the spirits and seems easily scared and shy, as she didn't even attempt to get away from or stand up to Magari Mizuki when she manupulated her into doing her dirty work for her.
Mirai has gone to visit Ayumi Shinozaki in the hospital. She comforts her and sympathizes with Ayumi's loss. Mirai reveals that she was the last person Hinoe contacted before she died and her last wish is for Ayumi to retrieve the Book of Shadows, which Shinozaki family has passed down for generations. The book must not fall into the wrong hands, otherwise the world will be plunged into a total chaos.
She gives Ayumi Makina Shinozaki address and tells her that she and the other Wiccans couldn't enter Makina's room because they are too strongly connected to the spirit world, making them really sensitive to the spirits. After Ayumi agreed to Mirai's request, she left the hospital room.
It turns out at least part of all that was a lie and was staged by Magari Mizuki who was threatening Mirai. Mirai runs off after Magari dismissed her.