Casualty Assistance Officers and Casualty Notification Officers are required to be equal or higher rank than that of the deceased.
We do not know what you mean by "cao".
A CAO must hold a rank of Sergeant First Class or above. CAO stands for Casualty Assistance Officer. Normally, the CAO is a member of the casualty's unit.
A Casualty Assistance Officer must be of equal or higher rank than the casualty. This is also true of the Casualty Notification Officer.
To unlock Cao Cao, you must clear Musou mode with two other Wei generals
SFC or higher
captain and above
Cao Cao has written: 'Cao Cao shi wen xuan'
captain and above
Cao-Cao was born in 1973.
Cao Cao died when he was sixty years old.
Cao Cao's invasion of Xu Province happened in 193.
Defeat Cao Cao 4 times. Defeat Xiahou Dun, Xu Chu, Cao Ren, and Dian Wei. Meet with Da Qiao after she appears for a cutscene. Achieve 150 KO Count. Method 2 : Defeat Cao Cao 4 times. Defeat Xiahou Dun, Xu Chu, Cao Ren, Dian Wei, and Xiahou Yuan. Achieve 100 KO Count. If you defeat the 4 generals (Xiahou Dun, Xu Chu, Cao Ren, Dian Wei) before Cao Cao's 4th appearance, they will re-appear, forcing you to defeat them twice unnecessarily. So wait until after Cao Cao's 4th appearance then defeat them to minimize trouble. A convenient thing to do would be to deplete the 4 generals' HP down low and leave them, then come back and defeat them after Cao Cao's 4th appearance. Both methods must be done in Expert.