The thing Cambion regretted most in his life was accepting the summons.
Originally he was just a cambion scraping by in the Blood Wilderness; life was tough, yet he was free. However, the bloodline of ambition always flowed in the veins of a devil, and Cambion often dreamt of climbing higher.
He imagined one day, he could don a crimson robe, stand atop the ramparts of the Blood River Fortress, overlooking the miles of bloody battlefield.
He also fantasized that one day he could enter Duke Zariel's Official Residence, become a member of her elite battle group, equipped with the finest Hell Engines, receiving respectful salutes even from other Devil Lords.
He really wanted to be that impressive.
So when he sensed the summons from Duke Zariel, Cambion immediately responded.
Although he knew in his heart that the real Duke Zariel would never summon a cambion like him—a dime a dozen—he guessed it must be an army under Zariel needing some cannon fodder.