Day 1: Mythology "give me a lesson in damnation"
Korra is the Persephone to his Hades.
~
Long ago, when spirits ruled over the earth in vengeance and jealous rage, the Titan Yakone ate his children out of fear. His youngest child, Aang, was hidden away and defeated his mad father—crumbling Titan reign and trying to bring about a new era of peace. Aang and his two elder brothers drew lots to determine which realms they would rule over. Amon, the eldest and most bitter, received the underworld; Sokka, the seas; and Aang inherited the air.
Amon was jealous of his brother Aang, and believed that he was tricked into picking the darkest and most dreadful realm. In hopes to appease his brother, Aang promised Amon a bride—his daughter, Korra, the spirit of springtime. Now Korra and her mother Katara did not know of this arrangement, so when Amon took Korra for his own and brought her into his realm, Katara washed a great wave over the earth and demanded her daughter.
Amon loved the beautiful Korra, and could not bear to see her leave. Likewise, Korra saw the man's sadness and pitied him—her kind soul could not let a man live a life of loneliness, when her hand could reverse it.
So, when her fiancée was not looking, she stole a single pomegranate seed, knowing her mother would demand her return. When at last Katara arrived, she threatened to flood Earth and overflow Amon's realm. Korra, seeing no choice, showed both the pomegranate seed, and ate it. "Now I am bound to you both," she said, "and so the Earth shall be spared and I shall gain a husband."
So it was decreed that during warm seasons, Korra would walk the earth that was almost flooded with her mother, and when Amon's power is strongest—in winter and in fall—she would stand faithful by her husband. Korra's decision saved the world, her husband, and herself.