Hero Faction
Siegfried
Cao Cao and Siegfried have been shown to get along well with each other, with the two being seen together, discussing their future plans and actions.
Georg
Like the other members of the Hero Faction, Georg deeply trusts Cao Cao and follows his orders faithfully.
Main Characters
Issei Hyoudou
Issei disliked Cao Cao since their first encounter, being angered by Cao Cao's actions such as trying to forcefully use Yasaka to open the Dragon Gate and injuring his friends.
Vali Team
Vali Lucifer
Vali and Cao Cao do not get along well but have been shown to garner great respect for the each other's abilities with Vali calling Cao Cao, the "Strongest Human", and Cao Cao willingly admitting that he can't defeat Vali in his Empireo Juggernaut Overdrive form.