In Chapter 69 of the Romance, Geng Ji is a man of Luoyang with the courtesy name Jixing who once served as a clerk in the Chancellor's office and was later transferred to Palace Attendant and Privy Treasurer, and he is on very close terms with the Director of Rectitude Wei Huang. Deeply resentful at seeing Cao Cao raised to the rank of king and using the Son of Heaven's carriages and robes when going out and coming in, he confers secretly with Wei Huang in the 1st month of spring in the 23rd year of Jian'an, saying that the traitor Cao Cao will surely usurp the throne and that as subjects of the Han they cannot side with evil men. When Wei Huang proposes drawing in Jin Yi, who is on close terms with Wang Bi, Geng Ji doubts that such a man would plot with them. Romance, Ch. 69 §25–26
The two go to Jin Yi's house, where Wei Huang, by way of pretence, asks Jin Yi to raise them up once the King of Wei receives the abdication, and when Jin Yi grows angry, Geng Ji chimes in that this is the will of Heaven and cannot be helped. Having confirmed that Jin Yi has a loyal and righteous heart, the two reveal the truth, and Jin Yi proposes to kill Wang Bi by acting together from inside and outside, seize his command and then join hands with Imperial Uncle Liu. When Jin Yi brings in Ji Miao and Ji Mu, the two sons of the Imperial Physician Ji Ping, whose father Cao Cao had killed, the five men swear an oath before Heaven and drink blood to seal their covenant. Geng Ji and Wei Huang each keep three to four hundred household servants and prepare weapons in advance. Romance, Ch. 69 §27–33
On the night of the fifteenth of the 1st month, when fire breaks out inside Wang Bi's camp after the second watch, Wang Bi mounts and goes out through the south gate, runs straight into Geng Ji, is struck in the shoulder by an arrow and flees toward the west gate. Alerted by Wang Bi, Cao Xiu holds off the rebels within the city, and Xiahou Dun, stationed five li outside the city, surrounds Xudu with a large army, and the fighting goes on until daybreak. When word comes that Jin Yi and the two Ji brothers have all been killed, Geng Ji and Wei Huang cut their way out through the city gate, but are surrounded by Xiahou Dun's army and captured. Romance, Ch. 69 §34 · 36–37
Cao Cao orders Geng Ji and Wei Huang, together with the old and young of the five families' kin, all to be beheaded in the marketplace. Dragged to the execution ground, Geng Ji cries out, 'Cao Aman! Since I could not kill you in life, in death I shall become a vengeful ghost and strike at the traitor!', and even when the executioner stabs his mouth with a knife and blood floods the ground, he keeps cursing until he dies. The Romance adds a poem by a later writer that begins, 'Geng Ji was devoted and loyal, Wei Huang was worthy.' Romance, Ch. 69 §38–40
Afterwards Cao Cao tells the officials who have been escorted to Ye Commandery that those who put out the fire when Geng Ji, Wei Huang and the others set Xudu ablaze should stand under the red banner, and those who did not should stand under the white banner. Saying that those under the red banner had in fact meant to help the rebels, he has them beheaded on the bank of the Zhang River, and more than three hundred die. Only then does Cao Cao grasp the meaning of the fire that Guan Lu had spoken of, and he offers him a reward, but Guan Lu does not accept it. Romance, Ch. 69 §41–42 · 44