Mizuha/Relationships

Fushi
While Mizuha doesn't "actively" know or remember Fushi, she reacts to Yuki saying his name by gripping her left arm. All of Hayase's successors carried a Nokker in their left arm, which indicates that she is related to Hayase's clan. When Hanna asks if she knows him, she answers with no, and adds that it just made her feel really nostalgic.

After learning the truth about her family, she decides that she wants to "obtain" him to become "truly perfect". With this, she follows the same goal as Hayase and her female successors. It's possible that Mizuha as well feels drawn towards Fushi romantically despite describing herself as a person fixated on logic alone. It's revealed later on that the Nokker inside her was influencing her feelings towards Fushi, making them appear like "true love".

Hanna
Hanna is Mizuha's only female friend. The two became friends one year prior. They seem like close friends, but Hanna is still somewhat awkward around her and doesn't think they're especially close. On the other hand, Mizuha wears the hair tie that she got from her every day. It's been hinted at that Mizuha might have romantic feelings towards her.

Yuki Aoki
Yuki has an obvious crush on Mizuha and even admits that the person he loves is in the club room while Mizuha is there. she does not reciprocates these feelings, but see's him as a good friend.

Izumi
Mizuha and her mother have a rather rocky relationship. Mizuha grew up thinking she was like a trophy to her mother, while her mother tried to keep her busy by filling her schedule to the brim with all kinds of hobbies and studies. After Izumi is taken over by a Nokker, however, Mizuha quickly comes to love her "new" mother. She even defends her in front of Fushi despite knowing that she is a Nokker.