Reine's commander but she treats Kotori more like a close friend rather than a commander for most of the time. Five years ago, <Phantom> knew that Kotori considered herself a crybaby, and was worried that Shido would leave her for it. Using this to her advantage, she tricked Kotori into becoming a Spirit by accepting a Sephira Crystal.
Reine treats Shido as an acquaintance, although she constantly messes up his name and calls him Shin (シン) instead of Shido. Compared to the rest of the Fraxinus' crew, Shido has a much easier time communicating with her, despite her habit of getting his name wrong.
However, for unknown reasons, Reine gave out a strange reaction when Kotori mentioned Shido was nearly suicidal and when Shido told her that she was like a mother. When disguised as <Phantom>, Reine has a connection towards Shido's mysterious past, admitting that she knows the reasons behind his powers and lost memories. However, she refuses to tell him on the basis that she knows nothing about his current situation and that Kurumi was eavesdropping on their conversation. However, <Phantom> apparently did something to Shido that she deeply regrets, as she states that she will not repeat her mistake again. Nevertheless, <Phantom> has shown a level of concern for Shido, saving him from being killed by <Dainsleif>. Also, despite being surprised at first, she was grateful for being able to see Shido again after the latter traveled back in time to 5 years ago, even saying that she would have to thank the Spirit of Time for arranging the meeting.
Reine and her vice commander, Kyouhei Kannazuki, do not interact much. However, during the side-story Kotori Mystery, when she checked his body after he was found unconscious, she said "unfortunately" upon discovering that he was still alive. This implies that, like Kotori, she dislikes him.
Reine's interaction with the Fraxinus's Crew as a fellow crew member is not seen or shown much in any media, but it is assumed that she interacts with them normally.
During the events of Yamai Tempest, Reine was attacked by a Bandersnatch unit, which Origami tried to push her out the way of before falling unconscious. After Origami woke up, Reine claimed that the AST solider saved her, despite the machine later found to be completely destroyed. Afterwards, Reine listened onward as Origami described her desire for more power, which she (as <Phantom>) later offered her under the guise of a Sephira Crystal that turned the latter into a Spirit.
Despite initially being surprised at Origami suddenly attacking her, Reine was impressed by how skillfully the former AST member used <Metatron>. After deducing that Origami had Kurumi send her back in time, <Phantom> admitted that she couldn't resist turning someone with such talent into a Spirit, even if she already knows that Origami will eventually turn against her.
<Phantom> was the person who told Kurumi about Shido's existence and how he had already sealed three Spirits, provoking Kurumi to transfer into Shido's class. After finding out that Kurumi's motives were to kill the First Spirit, <Phantom> mocked Kurumi by calling her surprisingly gentle. Five years ago, after finding out that Origami traveled back in time with Kurumi's help, she remarked that she didn't think Kurumi was the type of person to lend her powers to others. There seems to be things that <Phantom> does not want Kurumi to know, as she refused to answer Shido's questions on the basis that Kurumi was eavesdropping.
<Phantom> appeared before Miku when she was considering suicide after her first career as a music idol was ruined because of false rumors. She then took advantage of her newly found hatred towards humanity in order to turn her into a Spirit. <Phantom> offered her a Sephira Crystal while saying that it will give her the power to change everything.