| Yuki Niseko|
|School||Sankai High School|
On winter break, she went on a snowboarding trip with a group of students including Appi. On the last day, she was asked by Appi to meet him in front of a red snowmobile, but he didn't show up and she caught a cold as a blizzard started. She was even more angry at him, for not even making eye contact on the train ride back.
Shortly after, she would get followed by an invisible Snowman, which causes freezing temperatures anywhere she goes. While Rinne solves that strange case, she learns why Appi failed to show up, and that not only Appi but 2 other students who were in the snowboarding group had planned to confess to her and hidden their gifts in the snowman. After the snowman is dealt with, the 3 boys ask her to choose between them, but she reveals that when she was shivering next to the red snowmobile, she met a part-timer who took her back to the ski lodge on his red snowmobile, and they are dating now.
- As a student of class 1-4, she appears more often in the anime.