I found myself musing that The Nameless is a survivor of or a creation stemming from the farm. Even the frist 5 rules could be warped into the rules the guards had for the farm (just a guess mind you)
1.Don't let them kill each other
2.Don't put five or more together
3.Don't let them leave
4.Don't let them look for someone with a plan (Im stretching on 4 and 5 I know)
5.Don't let them impersonate the guards (obfuscate)

The Nameless might be someone who was broken (mentally) by the farm or could be something more supernatural; like a bunch of the dead...