Elliot Baldwin Woodman[]
As Woodman's secretary, Karen is often seen helping him move his wheelchair. She is in love with him and is not afraid of confessing her feelings in front of him or anyone else. Despite knowing that he is already in love with the Spirit of Origin, Karen remains resolute to remain by his side. She also showed hesitation over allowing Woodman to use his CR-Unit, knowing that the repercussions would greatly shorten his remaining lifespan. During the final battle, she half-seriously suggests that they abandon Ratatoskr to start a family, but she still respects his decision to sacrifice himself for the Spirits.
Ellen Mira Mathers[]
Karen is currently not on good terms with her sister. She tells Elliot that she understood years ago that she and her sister would not get along after Elliot told her that a future confrontation with DEM was inevitable.
Sir Isaac Ray Pelham Westcott[]
As one of his three surviving childhood friends, Karen also has key insight into Westcott's personality. Noticeably, she describes him negatively as a sociopath who would gladly press the button of a nuclear warhead just to satisfy his own curiosity. She is also familiar with how childish he is at times, describing his behavior after acquiring his new Demon King to a boy who wants to show off a new toy to a friend. Nevertheless, she still cared about him enough to be present to watch his final moments.
She is the only one out of Westcott's childhood friends who does not call him "Ike".
Origami Tobiichi[]
Due to her and Origami's similar personalities, the two quickly bonded. After Origami complimented the resolve of her love and dedication towards Elliot, Karen, in return, thanked the former AST Wizard for the praise. She reveals that Origami is the third person to have said that about her.
Kurumi Tokisaki[]
Karen's impression of Kurumi immensely soured after the Worst Spirit decided to mock Woodman repeatedly during Ratatoskr's 30th anniversary party. Before leaving the party with Woodman, she gave a particularly nasty glare to Kurumi.