Amok

The Amok, also known as Savages, Reavers, Gone or Defilers, are the survivors of the now obliterated megalopoli of Liberty City. This was the city that had reached the highest level of technology by the end of the World of Before, so the people inside its sealed walls soon attained the best possible living standard. Its inhabitants had little to do, as everything was programmed, scheduled, computerized and made possible mechanically by the governing council that kept all daily routines going. And an idle, jaded and aimless society quickly turns into a decadent, apathetic and dangerous one.
Ambrosia, a very strong psychotropic designer drug, washed over this society like a wrecking ball. Its origins are still unknown and uncertain (some say it was introduced in the megalopoli by a foreign agent intent on its destruction), but recent researchs have determined that the main component of the drug must be extracted from the hypothalamus of a person in the moment of their greatest suffering.
Its rise was meteoric. Each person was affected in a different way; some started to experiment hallucinations or visions, others could not stand the experience and took their own lives, many suffered paranoia and fell into madness and savagery, while others had their minds expanded into new areas of enlightment that transcended the human sphere. This plague raged on throughout the city, leaving behind it a trail of murders, suicides, serial killings and mental illness, until the Liberty City council decided to set up the old island of Manhattan as a prison-asylum of sorts to keep the disturbed inside, building a wall all around its perimeter.
But in an ironic twist of fate, inside the walls of Mahattan, free from the influence of this devastating drug, its effects diminished and most of the imprisoned people could finally make it. Outside the walls the Ambrosia was still raging on in full strength and the local council wasn’t able to control its effects. With the local law enforcement forces overrun, daily chores unattended and population in a permanent state of paranoia or extreme madness, the city fell. It’s not known where the actual collapse took place, but those now known as the Amok gathered in wolf packs and hunted down anyone weaker or not affected by the Ambrosia. Once Liberty City was a ruined and sacked city and no new victims or challenges remained inside it, the terror of these savage wretches, its minds ravaged and perception of reality severely altered by the Ambrosia, spread into the Wasteland.
Now they wander those barren lands in search of victims that make them feel something again, Harvesters always looking for the meager drops of drug they can distill from their prey. In their current state some of the Amok have started to mutate, as if the beast within had found a way to manifest itself in the outside. For some reason some of the tortured victims, their brains completely shattered, embrace the Amok after all the suffering received, turning from prey to hunters.