The slums on the south side of the river were called the House, not be the authorities, but by the people that lived there. The authorities refused to believe that anything even existed to the south of the river, and they only ventured into the House when they absolutely had to.
It was named as such because of the way people lived there - as one big family. Of course there were opposing parts of the entire area, but for the most part, people worked together, and wherever you went, it felt as though you were home.
As Nero jogged, slowly drying as their air rushed past him, he looked around for the familiar areas of the House: the large pillar of smoke from the permanent bonfire that people just loaded with things they didn't want and let burn; the structure that stood at two levels tall, higher than anything else in the area; and the masses of gangsters that hung around outside a building that was built primarily underground, where they could hide out in relative safety from any enemies that may have had.
Nero had run afoul of several of these different gangs that roamed the House, but none as eager for his blood as Fraser was. He hoped that the police force in the city would hold him and a few of his gang there for as long as possible - Nero relished the safety.