Colonel Sangross is the steadfast butler and second-in-command to Prince Walter Walzac of the Walzac Republican Empire. Approximately 60 years old, he displays unwavering loyalty and strict discipline toward his master. Beyond his butler duties, Sangross leverages connections within the empire's robot development ministry, sourcing and providing robotic arms designed to Walter's specific operational concepts and needs.

His core function involves managing Walter's logistical and tactical support, including overseeing the deployment of specialized mecha like the Custom Gear variants. Sangross remains a constant presence in Walter's activities, maintaining his duties even after Walter's shift from antagonist to protagonist. Following Walter's adoption of the new identity "Captain Eater Izak," Sangross continues his service, demonstrating steadfast allegiance regardless of his master's changing allegiances or goals.

Characterized by reliability and professionalism, Sangross undergoes no significant personal evolution or detailed backstory. He functions primarily as a stabilizing force within Walter's operations, executing his responsibilities efficiently and consistently within his established role.