Hell did not contain only demons, and demons were not all hulking, inhuman monsters.
Just as Schiller had said, God's aesthetic standards in creation were fundamentally consistent. Aside from certain races that had evolved later and were more naturally uninhibited, the older a demon was, the closer its form was to that of humans—or rather, to God's own form.
There were quite a few humanoid races in Hell. Demon Lord Belial belonged to the most famous ancient demon race. These demons also had two legs, two arms, and walked upright. Other than their skin colors differing from humans' and their more ferocious features, they were almost no different from humans.
There were also the Shadow Demons that frequently harassed the human world. They looked like human shadows and, aside from a pair of wings on their backs and their entirely black bodies, were humanoid as well. There were also many shapeshifting demons who roamed the human world and deceived humans. Sometimes, they maintained human forms too.
In addition, Hell contained human dark mages, cave dwellers, Protoss, and ancient rebel races. There were even some lucky human souls who, due to mistakes in their bargains, had failed to pay the price and ended up stranded in Hell's wild lands.
Therefore, humanoid creatures and human souls appearing here were not uncommon. Nor did every demon have the ability to take a bite out of a soul.
To put it bluntly, there was no clear dividing line between human souls and demon bodies. Being able to directly devour a human soul meant being able to directly devour a demon. Those capable of that were either powerful Demon Lords or battle-hardened Demon Generals.
If every little Hell grunt could tear apart and devour its own kind, Hell could not possibly have operated stably for