Long, long ago, the land of Termina was first created. The wise and benevolent creators who would one day be known as the Four Giants immediately took it upon themselves to create two entities that would protect the new land where they could not interfere with mortal affairs. These two god-like entities were fashioned with the use of the Four Giants' strongest magic, created to serve and protect the mortals that inhabited the land. The Four Giants knew their creations as Majora and Oni.
Despite the Four Giants' benevolent magic at work within them, these entities were far from perfect. Each had a vaulting desire to protect and control the land alone, each seeing the other as a threat to the peace, and eager to please the Four Giants, they competed with each other for power.
Neither of them were allowed to show themselves to the people, but both of them quickly began to break that rule. Majora appeared to the innocents of Termina as a thief and a trickster, and all soon learned to fear his deadly deception. Oni appeared to them as an angry god, demanding regular offerings on pain of horrible consequences. He was soon labeled by the people as the "Fierce Deity."
The Four Giants, angry and disappointed with their creations, ordered that their contact with the people be broken at once. The two entties lost their titles as Protectors of Termina. Majora and Oni disregarded that order, and soon broke out into total war, wreaking havoc and nearly completely destroying parts of Termina in their efforts to destroy the other.
The Four Giants immediately took action. In order to preserve Termina and keep it as safe as possible, the Giants used one of their most powerful curses on the two. They were both turned into masks, imprisoned within the deepest, darkest part of the realm for all eternity, and were stripped of their god-like powers. Though they still possessed incredible magic powers, they were no longer demigods.
Feeling shamed and responsible for their two failed creations, the Four Giants promise never to allow Termina to be in danger again, removing the memories of Oni and Majora from every mortal in Termina as they rebuilt the land, making sure that none would ever speak of the events that happened there.
Fearing of the future in which their creations might free themselves, the Four Giants hid Majora's Mask and the Fierce Deity Mask away carefully within the realm for the troubled and vengeful spirits to rest.
Still, the Four Giants' creations are not entirely forgotten. The spirits of the once-great are still confined to those masks; their hatred and of their masters has spread to a hatred of Termina itself. They cannot be freed unless someone wears the mask, in which case the entities would enter their body and exert control.
The masks remain undiscovered to this day...
...or so the Giants thought...
