Deng Ai appears at the Battle of Wu Zhang Plains under the forces of Sima Yi and Wei. In the Wei version of the stage, Deng Ai appears as an officer under Zhong Hui, who sets up the catapults in order to repel the Shu forces. In the Shu version of the stage, it is Deng Ai who sets up the catapults, not Zhong Hui, who instead appears as reinforcements later in the stage.
For his playable appearance, Deng Ai is a Wei general who once acted as a minster in office. After witnessing Sima Yi's intellect, however, he decided to return to the battlefront and watch over the troops during the campaigns against Shu. He has a hobby of looking at maps and, to preserve their accuracy, he is cautious of the war changing the geography.