Meng Ji is a military officer in the Taibai Empire's forces. His surname translates as "Ignorant" and his given name as "Jealous," traits that shape his motivations. He holds authority under Empress Cheng but deeply resents Pu Zhao, a former slave risen to Chief Engineer. Meng Ji repeatedly seeks to undermine Zhao, deploying Zhao's untested constructs against rebels and causing devastating losses that humiliate him. His antagonism includes schemes to expose Zhao's actions, such as sheltering the wanted rebel Ning.

Meng Ji allies with Lady Pang, a sorceress involved in court intrigue and plots to assassinate Empress Cheng. Their alliance aims to discredit Zhao and destabilize the Empress. After Lady Pang's assassination attempt fails, Meng Ji launches a coup d'état. He seizes control of the Zhengtian, an incomplete but operational flying superweapon fortress capable of mass destruction, and imprisons Zhao.

His ultimate fate remains unresolved following the coup. Rebels, including Zhao's childhood friends Fu Yin and Fu Ning, storm the Zhengtian while Meng Ji commands it against them.