Arda

Arda is the world of the Lord of the Rings continuum, on which the landmass of Middle-earth is located. Other lands on (or around) Arda are Valinor and Númenor.

While many Sues try to claim this world as their home, Arda is usually rid of them with the help of the PPC.

Alumia
There was, however, one very notable occasion when a Mary Sue, Alumia, merged with the entire world. This required a mass exorcism with the help of every available Agent.