Mio Ibuki/Relationships

Kakeru Ryūen
For unknown reasons, she is always by his side as one of his followers however, it is clear she doesn't enjoy the pain he inflicts on others as shown when she flinched after he smashed a glass bottle on the head Daichi Ishizaki or when he had Albert Yamada beat Daichi and the others for their failure in getting Sudō expelled. On the cruise, she angrily confronted him and made it clear that she couldn't stand nor approve of their cruelty and wanted them to stop their actions. She also doesn't tolerate him ignoring her words or treating her like a plaything when he made advances on her. After he tried to leave, she called out to him but Yamada intervened and Mio was angry and disappointed that he manipulated him into being his pawn before Yamada threw her down and Kakeru grinned at her pain.

Albert Yamada
While nothing is known about their relationship, it appears that she knows him very well as she was shocked that he would grab her and throw her on the ground after she tried to confront Kakeru. Mio voiced her disappointment in him for becoming a follower of Kakeru as he looked at her with an unfazed expression and walked off.

Kiyotaka Ayanokōji
The two first met on the school cruise where he witnesses her being knocked down by Albert Yamada after being shunned by Kakeru Ryūen. He goes to help her up but she angrily slaps away his hand telling him to stay out of her business before running off.

They met again the survival test where he finds hurt for unknown reasons, he even found himself stopping Haruki Yamauchi from approaching her, due to having suspicions about her, he soon says it was nothing, as they offer her help, by letting her come to their base camp. Though she refuses help from an enemy class, she accepts their offer and returns to their camp but makes it clear she isn't trying to be friendly with them.

After a night where a panties are stolen, Mio later talks with Kiyotaka asking if he believes she was responsible for the underwear theft but he says that he knows she didn't do it to her surprise. He states that while the other students in his class don't trust her he does which causes her to blush and nervously thank him for having belief in her. She was also seen curious, as she glanced back from behind, when Kikyō Kushida and Haruki Yamauchi commented on how, incredibly close Suzune Horikita and Kiyotaka Ayanokōji have gotten lately.

After the survival test, it is revealed that Kiyotaka knew she was a spy and he outsmarted her by using various tactics which helped his class pass the test. In the spin-off volume of the light novel, both her and Kiyotaka were seen together wearing casual looking clothes and heading for a fortune teller.