On the first day of High School she approaches Yuuta and reveals to him that she knows about him being the Dark Flame Master. Therefore she knows that Rikka has chūnibyō and in the beginning of the anime series, Yuuta tries to avoid Rikka due to the fact that she has 8th grade syndrome (something he is trying to forget and leave behind). On that same day Rikka loses her wallet, and Yuuta is forced to take her home due to the fact that Rikka lives a floor above Yuuta's apartment. From this point on Yuuta seemingly takes on the role of a caretaker. When Rikka runs away from her grandparent's home, Yuuta chases after her; When Rikka forgot her key and they stayed at Yuuta's apartment alone for the night, at this point, Yuuta begins to wonder about his feelings for Rikka. During the preparation for the school festival, Rikka slips off the roof of the school building but is saved by Yuuta. After being rescued by Yuuta, Rikka refuses to let go of Yuuta because she is still in shock and the two embrace. After some initial awkwardness Rikka is able to confess to Yuuta first and the two formed the "Tyrant's Eye's lover's contract". When Tōka reveals that she will be leaving for Italy, and that her mother will be taking care of Rikka, Yuuta tells Rikka to take off her eyepatch. This prompts Rikka to leave behind her chuunibyou and loses her powers. When Rikka decides to move back in with her grandparents, Yuuta is confused but soon realizes he was the cause of Rikka's departure. After reading a letter he sent to himself from his days as the Dark Flame Master as well as later learning (from Kumin) about how Rikka began with her chuunibyou, Yuuta races off on a bike borrowed from Isshiki to Rikka. Yuuta (who now accepts his and Rikka's chuunibyou) asks Rikka to form a contract with him. Rikka realizing that Yuuta is accepting her for who she is, leaps into his arms to run away from her grandparents and the two are reunited. Yuuta helps her find the "Etheral Horizon", so that Rikka can say her goodbyes to her papa and move on. At the end of the series, Rikka regained her powers and the Tyrant's Eye and it is revealed that the Rikka has returned to living in the apartment above Yuuta's. Yuuta fully accepts her chuunibyou knowing the importance of it, but still finds it embarrassing.
Yuuta met Nibutani by accident whilst coincidentally arranging their looks at the train station. After realizing that she was the class representative and his classmate, Yuuta developed feelings for Nibutani, prior to establishing a close relationship with Rikka. He had imaginations of Nibutani harboring feelings for him. The two got along well with each other especially when Yuuta becomes unintentionally a class representative. At some point, Nibutani asks Yuuta out on a date, but it turns out to be only a act for her to find her book and destroy it, thus revealing her chuunibyou side. Like him Nibutani wishes to get away from her eighth-grade syndrome. This made him empathetic to Shinka and no longer has feelings for Shinka, though he understands her and continues to assist her in her life problems.