Qu Hai is an original member of the Hi Shin Unit, joining during its formation as a 100-man squadron at the Battle of Bayou. Serving as a squad leader directly under Ri Shin's command, his early membership places him within the unit's core veteran group. He participates in the Hi Shin Unit's numerous campaigns as it grows from a small squadron into a powerful independent army, demonstrating consistent combat effectiveness throughout. During the Western Zhao Invasion, Qu Hai achieves significant recognition by killing the Zhao general Kin Mou in combat. This feat contributes directly to the Qin Army's right wing advancing towards the enemy headquarters and earns Qu Hai a promotion to the rank of 300-man commander. Concurrently, he is appointed co-leader of an archer unit alongside Sou Jin, marking an expansion of his tactical responsibilities. Qu Hai remains an active commander as the Hi Shin Unit evolves into a 60,000-man specialist army, serving under the command structure led by Ri Shin and Kyou Kai. His position is confirmed among the unit's personnel following its reorganization and reinforcement after the Hango Campaign.