Jin Cheng

After Vera's death, Jin visits Vera's mother, Ye Wenjie, and leaves with a virtual reality headset that seems to have belonged to her friend. The game shows a world with runaway suns, where entire civilizations die of heat or cold. Jin tries to predict how the suns move and starts clearing levels. Every time she seems to crack the pattern, another extinction wipes out the civilization, and the game starts over in a new era, with new sages trying to explain the sky.

Jin brings her friend Jack into the game. In the Mongol capital of Shangdu, Isaac Newton and Alan Turing build a human computer made of soldiers. Jin predicts an alignment of three suns and gets it right, but the civilization is wiped out again. Soon after, Jack quits the game and is murdered at home by Tatiana.

At the request of Da Shi and Thomas Wade, Jin joins the movement tied to the game. At a ceremony she watches Ye Wenjie reveal herself as its leader and survives the police raid. After the ship Judgment Day is destroyed in the Panama Canal, Jin goes back into the headset with Wade, and the two meet the San-Ti's avatar. Her boyfriend, Raj Varma, a Royal Navy commander, also joins the operation at Wade's invitation, and Jin's personal life gets more and more tied to the war ahead.

With the world in a panic, Jin joins the group planning the defense against the San-Ti fleet. She proposes the Staircase project: a probe pushed by nuclear bombs all the way to the enemy fleet. Meanwhile Will, another of the Oxford Five, spends his inheritance to buy her a star, DX3906.

The probe can carry only a human brain. Will, dying of cancer, agrees to euthanasia so he can be the payload, and Jin rushes to stop him but arrives too late. At the launch from Cape Canaveral, everything seems to go right until a sail tether fails and knocks the probe off course. Crushed, Jin is taken by Da Shi, along with Saul, to a swamp full of cicadas: proof that bugs survive everything.

Jin doesn't exist in Liu Cixin's books. She combines parts of two characters: researcher Wang Miao from the first book and engineer Cheng Xin from Death's End. She doesn't appear in Three-Body, the Chinese series.