One thing I noticed while we were making our way there was the fact that there were a lot of monsters and slaves, all of them wearing a collar around their necks.
If I remember correctly, this particular country was known for their taming and training skills. Thus, new slaves and captured monsters would be sent here to be trained and tamed.
That would explain why there are so many slaves.
Even along the path, I saw people of different races with collared necks being led by several guards watching over them. Not two feet away from them would be a monster with a similarly collared neck either kept in a cage or being used as a beast of burden.
We reached the gates without incident and there seemed to be some kind of checkpoint in front of the gates that everyone had to pass before entering the city.