Avatar: the Last Airbender/Legend of Korra

Earth.

Fire.

Air.

Water.

As a result of their connection to the Elements, the citizens of the Four Nations - both Bender and Non - have strong sexual urges and so encourage a Free Use society so as to maintain said connection.

Due to being the only being to Master all Four Elements, the urges of the Avatar are stronger than any other and so it is their duty to ensure the continuation of Benders of all Nations, either by knocking up or being knocked at any given opportunity.

so who is the Avatar of our story?

option 1: 18 year old Aang is freed from his confinement after 100 years during the War against the Fire Nation, and is determined to bring back the Airbenders.

option 2: 18 year old Korra is the new Avatar and a complete slut. When she moves to Republic City to complete her Airbending Training she finds a city full of lust and in need of a hero.