Younger Brother's Folly
The group referred to as The Birthright has no actual name for themselves, as they do not care for such labels. The name comes from their tendency to say things such as "we are your birthright" or "we are what you deserve", usually when one of their victims ask them terrified questions shortly before death.
The Birthright are the scions of a powerful Shadowed, Kla'en, who came to believe it was his duty to punish the denizens of The Folly for their sins. The members are zealots every one, who care for nothing other than bringing pain and misery to every soul in The Folly. All members share the blood of Kla'en and thus are gifted with various eldritch powers. Often living in the streets, they are like a plague moving through the world. They believe that as the source for all evil in existence, every person in The Folly deserves the most horrific of punishments, and they consider it their sacred duty to carry out such punishment. They see any such enterprise as worthwhile, from the torture and murder of a single soul to the corruption of an entire kingdom.