Zhengyi subdued Arctigis centuries before when the wizard was still a living being.
Arctigis was a cruel and vicious being, who loved tormenting the weak. He truly enjoyed making illusions that had a captive believe they had the possibility of escape and then snatching that hope away. However, Arctigis had learned to be cautious in approaching powerful enemies.
In his twisted way, Arctigis loved Zhengyi and he would do anything to avenge his death, not caring for his own safety.