The undercity is basically a wilderness around the bases of the giant skyscrapers of Taris. It was typically reserved for exiled criminals and eventually, their descendants. Despite the dangers of wild beasts, the Rakghoul, and widespread disease, many people are turning to the Undercity as a less crowded alternative to the overpoulated Lower City. This has resulted in an increase in the already high levels of disease and has caused an explosion in the Rakghoul population, as a sentient infected by a Raghoul becomes a Rakghoul themselves.