Courtesy name Fengxiao. Guo Jia is the fourth member of the Eight Enima, genius military advisors handpicked by the renowned veteran strategist Sima Hui 'Shujing' from his students. He's praised as the 'King of strategic decisions', a nod to his ability to account for virtually every scenarios possible in his plans. Like his close friend, the Third Enigma Jia Xu, Guo Jia is also a proponent of the 'Darkness ideology', which hails actions of utmost cruelty, rather than of benevolence, as the ultimate mean to pave way for peace and prosperity. This, while perpetuates his fame as Cao Cao's 'darkness', also strains his relationship with his upperclassman and comrade, the Second Enigma Xun Yu.
Much to his despair, Guo Jia is afflicted with a terminal illness (possibly tuberculosis), which dooms him to a premature death. Guo Jia has long since resigned himself to fate, reluctant to enter anyone's service, until Jia Xu persuades him to join Cao Cao, a warlord they both deem worthy of serving. Since his entrance, Cao Cao's influence has expanded vigorously, soon to equal that of the Yuan clan.