The most popular theory is that the first throwbacks were people the Shiva Virus caused to devolve, changing them into something that more closely resembled their primitive ancestors. They can’t talk, they only use the most basic tools, and they have no culture or society to speak of. There’s a similar group of mutants lurking under the Province called the Underdwellers. These pale, humpbacked bastards can be found in a lot of the old GlobalTech facilities, as well as in mines and old sewers. They’re faster than the Throwbacks, but not as tough. Underdwellers possess wicked edged weapons they use to hunt down their prey—which includes humans.