A jovial but astute psychologist at Saro University who specializes in the mental effects of isolation and darkness. He is initially called to investigate a disturbingly effective "Tunnel of Mystery" amusement park ride, which triggers extreme claustrophobic reactions in the populace. He later joins the astronomers to provide expertise on the potential psychological catastrophe of the coming eclipse.

A pragmatic and somewhat cynical archaeologist who discovers the charred ruins of multiple ancient civilizations layered on top of one another. Her findings suggest a cyclic pattern of global destruction by fire every 2,049 years, providing historical evidence that corroborates the astronomers' theories. She is independent and career-focused, often prioritizing her work over personal relationships.

A young, capable astronomer at Saro University who is deeply loyal to his mentor, Athor 77. While conducting routine observations, he discovers a gravitational anomaly in the orbit of the planet Kalgash that challenges established scientific laws. His discovery serves as the catalyst for the realization that an unknown celestial body is approaching the planet.

A sharp-tongued journalist and columnist for the Saro City Chronicle who is known for his skepticism and challenging interviews. Though he initially intends to debunk the scientists' "doomsday" predictions as hysteria, he finds himself drawn into their inner circle as the evidence mounts. He maintains a complicated friendship with Beenay and a romantic interest in Siferra.

The elderly and respected director of the Saro University Observatory and the "grand old man" of Kalgash astronomy. He is the architect of the Law of Universal Gravitation, the scientific foundation of their society. He faces a professional and personal crisis when his own life's work is proven insufficient to explain the impending catastrophe.

An influential leader and spokesperson for the Apostles of Flame, a religious cult that preaches the world ends in fire every two millennia. He possesses ancient scriptures that uncannily predict the astronomical events the scientists are just discovering. While outwardly fanatic, he is politically savvy and negotiates with the scientists to prepare the world for the "Stars."