As Kara's eccentric and loyal confidant, Simon embraces the bizarre and unexplained with ease. His idiosyncratic nature and unique perspective on reality make him an essential ally in uncovering the mysteries they face.

Kara's uncle, who owns the Wonder Museum, embodies kindness and inclusivity, offering Kara a safe haven. Though mostly off-screen due to knee surgery, his influence and values permeate the story through his beloved museum.

The enigmatic and otherworldly antagonistic force associated with the willows, characterized by its unknowable and alien nature. They represent a constant, unsettling presence that compels the characters to confront the fragility of their understanding of reality.

Kara's ex-husband, who represents the conventional life she has left behind. His presence in the narrative highlights the contrast between superficial comfort and genuine emotional security.

A park ranger who becomes a crucial figure in understanding the otherworldly threats. His experiences and testimony provide insight into the nature of "Them" and the rules of survival in the unfamiliar world.

Beau is Kara’s cat, who serves as a reliable early-warning system against danger. The taxidermy within the Wonder Museum adds a quirky ambiance, but its presence becomes significant in the face of impending peril.