Gruelling Devil–a subspecies of Devils that roamed around the barbaric areas of Hell, as myths had it. Gruelling Devils were known as the Guard Dogs of Hell, and were the most physically adept.
They had an extreme, barbaric personality and a tendency to sort matters out through gruelling battles that usually resulted in death, hence their name–Gruelling Devils.
However, despite relying mostly on the physical aspect for battle, Gruelling Devils could also wield mana naturally, while the proficiency depended on their lineage. This made them terrifying all-rounders in certain cases.
Although treated as third-class citizens within Hell and unable to enter the innermost parts of the realm, Gruelling Devils were usually more powerful than most regular Devils, naturally. It was only their lack of refinement and conditioning that led them to be weaker in the long run.