Satone Shichimiya/Relationships

Yuuta Togashi
Satone is shown to have a crush on Yuuta in the past and throughout the series. They were fellow chuunibyous in the middle school and often rubbed each others' noses as a sign of alliance (Or mana transferring/sharing). She had transferred schools much to Yuuta's surprise because he had heard nothing of it. After re-realizing her feelings for Yuuta, she decided to demolish those feelings to not hinder the relationship between Yuuta and Rikka.

Rikka Takanashi
Rikka initially viewed Satone as a threat to her contract with Yuuta. She gets jealous when Satone gets to close to Yuuta. Because of their chuunibyou personas, both Satone and Rikka would challenge each other to delusional duels, as seen when they first met. Eventually they became friends after Satone told Rikka of her feelings for Yuuta and how she got over it. Satone respects and supports the relationships of the couple, and had no intention to destroy the lover's contract between Yuuta and Rikka, even helping Rikka improve her relations with Yuuta.

Shinka Nibutani
Satone and Nibutani were friends in middle school, still remembering the days when she and Mori Summer performed rituals (to Nibutani's embarrassment and dismay). Nibutani gave attention to Satone's relations with Yuuta and Rikka. Eventually, Nibutani confirmed her suspicions when she learned that Satone had feelings for Yuuta, after she interrogated her in a manner similar as to how she interrogated Rikka. Nibutani was concerned about her, but Satone assured Nibutani not to worry for her and that she can fight her feelings.

Kuzuha Togashi
It is shown that when Satone goes to Yuuta's apartment, Satone recognizes her immediately and hugs her. But there are no further flashbacks on how they known each other, it is unknown if Satone visits their apartment oftenly during middle school. Since at the start of Season 2 Satone had known where Yuuta lives and transfers to a floor above Yuuta's apartment which was Rikka's old room, so it's possible that Satone really visits the apartment.