Ye Wenjie is an astrophysicist who endures extreme trauma during the Chinese Cultural Revolution. After witnessing her father's brutal murder, she is sent to a labor camp and later assigned to the secretive Red Coast military base. Her experiences with violence and environmental destruction instill a deep disillusionment with humanity, shaping her scientific career and her worldview.

Wang Miao is a grounded, practical nanomaterials researcher who becomes entangled in a global military investigation following a string of suicides among prominent physicists. Unlike abstract theorists, Wang is dedicated to applied sciences. His life is upended when a mysterious countdown begins appearing in his photographs and eventually his own vision, forcing him to investigate the Frontiers of Science and the enigmatic Three Body virtual reality game.

Nicknamed Da Shi, Shi Qiang is a blunt, coarse police officer brought in by the military to assist with the scientific crisis. Suspended from his regular duties for his unorthodox and sometimes violent tactics, he possesses a sharp, cunning intellect that contrasts with the academic minds around him. His deep understanding of criminal behavior and human nature makes him an invaluable asset to the Battle Command Center.

Wei Cheng is a self-professed slacker and a mathematical prodigy. Uninterested in standard academic or professional paths, he spends his days sitting at a high-end computer, obsessively calculating solutions to the notoriously unsolvable three-body problem. He leads a detached, apathetic existence, largely isolated from the chaos surrounding his wife's activities.

Shen Yufei is a Japanese physicist with Chinese heritage and a prominent member of the Frontiers of Science. She is deeply invested in the mysterious Three Body video game and holds enigmatic beliefs about the limitations of human science, instructing Wang Miao to halt his research to stop the countdown in his vision.

Pan Han is a notorious environmentalist with a track record of accurately predicting ecological disasters. He fiercely opposes technological progress, views human development as a disease, and aggressively harasses scientists connected to the three-body problem.

Ye Zhetai is a highly respected physics professor. He staunchly refuses to compromise his objective scientific principles or bend to political ideology, a stance that puts him in grave danger during the Cultural Revolution.

Shao Lin is a physicist who aligns herself with the radical revolutionaries during the Cultural Revolution. She publicly denounces her husband's scientific theories to protect herself and advance her own political standing.

Ye Wenxue is Ye Wenjie's younger sister. As a fervent member of the Red Guard during the Cultural Revolution, she eagerly issues scathing comments about her father and aligns completely with the radical student movement.

Bai Mulin is a journalist for the Production and Construction Corps. He shares Ye Wenjie's sorrow over the environmental destruction of the Inner Mongolian forests and introduces her to banned literature, setting off a chain of events that drastically alters her life trajectory.

Yang Weining is the head engineer at the secretive Red Coast Base and a former student of Ye Zhetai. He values practical experiments over theoretical discussions to avoid ideological missteps and helps bring Ye Wenjie onto the military project despite her political background.

Lei Zhicheng is the Political Commissar at the Red Coast Base. He represents the government's ideological interests on the secretive project, managing both the scientific personnel and the base's hidden overarching mission involving extraterrestrial communication.

Ding Yi is a theoretical physicist deeply shaken by recent, inexplicable failures in global particle accelerator experiments. His scientific disillusionment and personal grief represent the broader crisis facing the global academic community.

Yang Dong is a brilliant abstract physicist and the daughter of Ye Wenjie. Her sudden death by suicide, prompted by her belief that physics does not fundamentally exist, serves as the catalyst for Wang Miao's entry into the military investigation.

General Chang Weisi is a high-ranking Chinese military officer coordinating an unprecedented global coalition. He understands the gravity of the scientific crisis and recruits experts from various fields to combat an unspecified existential threat, working surprisingly closely with NATO and CIA counterparts.

Mike Evans is the billionaire heir to an American oil fortune who rejects his father's capitalist ideology in favor of radical environmentalism. His disgust with humanity's destruction of the natural world leads him to form extreme philosophies regarding the rights of all species on Earth.

The Princeps is the stoic, pragmatic leader of the Trisolaran civilization. Dictated by the harsh survival necessities of a world plagued by unpredictable Chaotic Eras, he suppresses emotion in favor of cold, calculated decisions for his species' future.

The Listener is a lonely Trisolaran stationed at Post 1379, tasked with monitoring the cosmos for alien signals. Weary of his civilization's spiritually monotonous existence, he makes a fateful, forbidden choice upon receiving a message from a distant world.