Yuuji Kazami Edit
Due to the difference in their personality, as well as Yuuji's lack of knowledge in treating women, they are usually at odds against each other. It has been implied throughout the series that Michiru might have had feelings for Yuuji, however, due to her determination in keeping up the tsundere act, she ended up being a nuisance to him.
During her route in the visual novel, after a misunderstanding the meaning of "first base", Yuuji kissed her. Unaware that her other self has initiated this before hand, Michiru fell into shock and confusion as to why he did that to her. The other "Michiru" has noted that the incident caused Michiru to fall in love with him. Since then, Michiru gradually opened up to Yuuji, one such example is asking him out on a "pretend-date" in hopes that they'll go in an actual date.
Yumiko Sakaki Edit
Due to their contrasting personality, Michiru and Yumiko doesn't seem to get along too well at first. In many occasions, Michiru's witty comments was seen as insult by Yumiko, often resulting with the latter threatening the former with a box-cutter.
However, they actually care for each other, despite their denial. One example of this is that Yumiko hesitated to give Michiru's 6 pennants, a souvenir she bought her from her trip oversea, due to the possibility that Michiru may dislike her gift. Yumiko valued Michiru as an important person in her life, such as when Yuuji informed everyone of her alleged death. She, while maintaining her composure at first, eventually broke down hysterically, much to everyone's surprise.
Amane Suou Edit
Michiru holds Amane in high regard as one of her valued friends. Though often questions Amane's slutty behaviour and morals.
Makina Irisu Edit
Makina sees Michiru as a playmate, second only to Sachi. Since Sachi is devoted to her work most of the time, she often spends time with Michiru. This was also revealed in Michiru's route, as her absence caused Makina to vent her boredom on Yumiko instead, testing her patience. Although Makina's jokes with Michiru are a little extreme, she still sees her as a really close friend. In Michiru's route, when Yuuji announce the girls of Michiru's "death," Makina is the first character to completely break down, saying that her death was "just messed up."
Sachi Komine Edit
Michiru and Sachi have a sort of a close relationship. It could be said that Michiru and Sachi are dependent on each other in some way. In the first season of the anime series, it seems that both are in a master-servant bond.
Chizuru Tachibana Edit
Meowmel (Nyanmel) Edit
Grisaia no Kajitsu
A cat found by Michiru one day on the hill near Mihama Academy. She took the liking to the cat so much that she starts seeing it whenever she has the chance. The feline was eventually tamed to the point it starts follow Michiru back to the school ground. When she's caught playing with the cat, she would try to deny any relationship with it, despite being transparent about her care for the cat.
Initially, due to her fear of losing anyone precious to her again, she tries to keep her distance from it while maintaining a good relationship with the cat. She calls the cat Nekonyan (literally means "cat-meow") as to not having any attachment to the creature. Eventually, urge by Yuuji to give the cat a proper name, she gave the name "Nyanmel" to the cat due to Yuuji constantly calling him "Rommel". From that, she slowly grow more attachment to the cat, considering it to become a part of her world.
Unfortunately, sometimes after naming the cat, Nyanmel was caught in a terrible car accident. When the cat was discovered, she becomes terrified at the sight of her bleeding friend. Despite Yuuji attempt to rush the creature to the veterinarian, Nyanmel pass away in Michiru's lap, to the girl horror. Nyanmel's death deeply hurt Michiru to the point she attempt to commit suicide by overdosing her tranquiliser shortly after, only to be saved by Yuuji.
Idol Mahou Shoujo Chiruchiru ☆ Michiru
Michiru met her when she was about to jump from the roof of their school in an attempt of killing herself,believing it was unfair that she had the courage to end her life. Soon after, they became best friends. Michiru was very worried when she left the school because of the rumors about her relationship with an older man and the photos of her having sex on the internet. After the man rejected her, she met up with Michiru on the same roof top where they met, and told her that the rumors that she have heard are true. The girl decided to end her life on the roof where they both met. Seeing her best friend jump off the rooftop gave Michiru a heart attack as she collapse in pain on the spot.
As Michiru's first "bestfriend", the girl has a very big impact on her life. Michiru did not let go of her friendship with the girl, and become very upset when the topic of "bestfriend" was brought up. Her death also led Michiru to believe that anything that comes to be important to her life will eventually be taken from her, and she desperately avoid becoming to close to things despite her obvious affection for the subject.