The Children of the Scarlet King were mentioned the first time in the article of SCP-231, where it's revealed that the cult kidnapped seven young girls and impregnated them via some occult ritual. Cult was raided by the police, in which one of the girls gave birth to something horrible, destructive and anomalous, so that Foundation stepped in. The six other girls were detained by the SCP Foundation, but five more births, and with that five more disasters, occured. Currently only the last girl, SCP-231-7, remains, and it is believd if she gave birth, a XK-class "end of the world scenario" might occur.
More information about the cult was revealed in the Global Occult Coalition case file KTE-2013-Kapala-Mendes. The GOC refers to the cult as GROUP MENDES, and knows about at least six cells of the organization: three in North Amercia, two in Eastern Europe and one in North Africa. Most of the members of the cult are from the lower classes of society, with the group having several wealthy backers as well. The group is also linked to other radical anomalous groups.
The main cell, located in Alabama, USA, presents itself as a standard right-wing Millenialist fire-and-brimstone Christian church, while it's inner circle reveals the true dogma: the worship of the ancient low-level elder god known as the Scarlet King, who is also possibly The Devil. The cult apparently believes that the king can win the battle of Armageddon, where it would destroy the planet, and allow the members of the cult to rule over the post-apocalyptic landscape. The group's dogma also includes a philosophy of "enlightenment through violation", which is speculated to resemble the rituals of Sarkicism, meaning vile acts rape, pedophilia, human sacrifice and cannibalism could be part of the dogma, as is thaumaturgy (magic). The GOC also describes them as "psychopathic demon-worshipers", who also have knowledge and access to at least one or more anomalous artifact/entity.
The current numbers of this group is speculated to be around 8000 actual cultists, and at least 60 000 "Second Amendment Activist" Christians, who have a paranoid mistrust of secular governments, and who are ready to defend themselves (and the actual cultists) through violent means. The group has gathered massive amounts of wealth, weapons and anomalous objects over the years, to the point in which the GOC cannot destroy them in secret.
Others believe that group simply just want to serve the King in his conquest to wipe out all reality, similiar to the cult of Cthulhu, wanting to both help and witness the cosmic destruction that he causes.
- The cult might be connected to the Daevites, an ancient and savage culture that also worshipped the Scarlet King. The tale New Job also desribes an ancient Daevite Tablet was a theogony for the Scarlet King and his Brides, which could explain the seven kidnapped girls. The brides themselves gave birth to monsters that serve the King, similiar to the seven girls. This could also explain the resemblance to Sarkicism, as it's followers also originated from the Daevites, which could explain some of the similiar practices.