The Purpose is the guiding principle of the Shadowlands, and it is the reason the Attendants exist in Oribos. It also keeps the realms of Death in balance. The Purpose is the belief that the Shadowlands follows a pattern laid out by the Arbiter in her infinite wisdom. It also decides what path each Attendant follows in Oribos: Caretaker, Scholar, or Protector.
According to Fatescribe Roh-Tahl, "All beings in the endless cycle serve the Purpose—even those who do so unknowingly or unwillingly." The Attendants of Oribos trust it so implicitly, some even claim that all souls flowing to the Maw must be a part of the Purpose. However, some Attendants have begun to question their faith in the Purpose as they cannot understand why the souls are flowing to the Maw.
Although the Attendants record where all souls are sent, only the Purpose may "reveal whether the threads of a soul will rejoin the tapestry of an individual existence."
The Purpose may be a form of ancient technology. Caretaker Kah-Toll says, "The Purpose is ancient. Possibly beyond your comprehension. This technology is divine." Though they may be referring to the vault in Oribos, it is possible they are referring to the Purpose and its machinery, which is present all throughout the city. The Purpose may have been constructed by the First Ones.