|Full Name||Mitsui Honoka|
|School||First High School|
|Voiced By||Sora Amamiya (Anime)|
|Novel||Volume 1, Chapter 2|
|Manga||Volume 1, Chapter 3|
|Anime||Episode 1, Enrollment Chapter I|
|Spin-off Manga||Volume 1, Chapter 3|
Shizuku is Honoka's closest friend and rival since primary (elementary) school. They both saw each other as a formidable opponent which drove them together since no one else could reach their level. Upon entering First High, and after witnessing Miyuki's unfathomable strength, she becomes the new bar for what they want to achieve.
Shizuku supports her desire for a relationship with Tatsuya, often giving her the push she needs to display her affections towards him.
Although the two of them are good friends, Honoka finds Miyuki to be one of her greatest obstacles in getting closer to Tatsuya. The two seem to share a bit of a rivalry in regards to gaining his affection.
In Visitor Arc, Miyuki helped Honoka get a chance on Valentine's Day to be alone with Tatsuya and give him chocolates.
Honoka is also the one who breaks the tension in the room whenever Miyuki gets upset (whether intentional or unintentional).
In Volume 17, Shizuku tells Honoka about how Miyuki is the next head of the Yotsuba clan. After hearing this Honoka is very surprised. But after thinking it over the fact that Miyuki’s power and skill cannot be compared, she is less shocked. Shizuku later tells Honoka about Tatsuya and Miyuki’s engagement which makes her cry.
At a later date in the Student Council Room, when everyone finishes their lunch, the atmosphere changes; Honoka speaks to Miyuki and declares she will not surrender her feelings towards Tatsuya. Miyuki responds that there is no turning back and she accepts Honoka as a rival.
In the spin-off manga, Honoka has shown great respect towards Miyuki for excelling in just about every test in the entrance exam. However, this respect appears to hinder Honoka a bit, as she constantly wonders whether she will ever become as good as her in the future.
In Volume 4, it is revealed that the first encounter she had with Tatsuya wasn't the incident that occurred shortly after the day of enrollment. The first encounter was on the day of entrance examination, as they were in the same testing group. At that moment, she thought that Tatsuya's magic was so beautiful that it was breathtaking and this also made her very angry when she found out that he was a Course 2 student.
Honoka harbours romantic feelings towards Tatsuya, and she has even confessed to him.
After hearing Tatsuya's circumstances as he cannot reject or answer her feelings, Honoka said she will still like him until the day there is someone else that she can like.
In Volume 10, these feelings are proven to be quite strong, as the Parasite inside Pixie has absorbed these emotions and has since then dedicated itself to serving Tatsuya. Also, she was the only girl within the 1st year females who had given Valentine's Chocolate to Tatsuya with a clear romantic meaning. Tatsuya could not return the feelings which she was already aware of so did not feel disappointed. Tatsuya gave her a return gift immediately and also told to expect another the next month which made her extremely happy.
In Volume 17, Shizuku tells her about Tatsuya and Miyuki’s engagement. Honoka initially thinks that this is a joke, but Shizuku had very serious and stiff expression. Honoka realising that Shizuku is serious gets out of her chair and runs. She is then stopped by Shizuku who struggles to contain her, causing her to lose her balance and falls to the ground. Honoka apologises and both of them goes to Honoka’s room. She begins to cry after asking Shizuku again if it’s true. She goes on to say Tatsuya said they were siblings and that Miyuki considers her as a friend. Shizuku’s tells her even though Miyuki’s feelings are different, Tatsuya only views Miyuki as a sister. Therefore Honoka still has a chance.
Shizuku goes on to say that nothing is set in stone and this also has to surprise Tatsuya. She mentions that Honoka has an option of becoming Tatsuya’s lover. However this is not now, nor when Miyuki becomes the head of the Yotsuba Clan, but when Miyuki and Tatsuya are married.
Shizuku asks Honoka if she is willing to give up on Tatsuya, Honoka says she isn’t. Honoka knows that Tatsuya has exceptional magic, and the Yotsuba will want him to leave behind a descendant. The road for Honoka is now difficult. She is not willing to give up on Tatsuya however she doesn’t want to snatch away her friend’s (Miyuki’s) happiness. A little while later, Honoka goes into the arms of Shizuku in bed.
Honoka didn't appear to like Morisaki very much from the start. In the spin-off manga, she immediately interrupted him while he was talking to Miyuki, after noticing how uncomfortable she was as he was berating the Course 2 students. She was also displeased when he forced Tatsuya's group to leave in the middle of lunch, and disliked the way they were trying to forcefully separate the Shiba siblings while talking down on the group.
Shizuku's parents consider her very much as their own daughter. Honoka also reciprocates their feelings, but sometimes she is embarrassed by their attention, like when Ushio gives her not inconsiderable amounts of pocket money every time they meet.