Zolgas was the closest human city to the demon territory.
It was a frontier city.
Usually, this characteristic would define it as a nucleus for commerce and one of the bigger melting pots of Ouroboros.
That would have been if the two confining states had good political relationships.
This was way, way far from reality.
The populace remembered the blood flowing in the streets during the war between humans and demons.
The conflict caused deaths, and those alimented fear mixed with rage in the hearts of humans and demons alike.
Before the war, humans differentiated between demons(warriors of the Demon King), monsters(animalistic creatures created by mana accumulation), and mythical creatures(monsters gifted with logical thinking and no affiliation to the Demon King).
The wars ended, but a cold war based on espionage and secret missions was still in action.
At this point, no differentiation was needed.
Every dead demon was a good demon as a past killer.