The Sacred Realm
Din: Long ago, there was no world. There was no land, no people, nothing at all. There was only chaos.
Nayru: Then, the three Golden Goddesses, Din, the Goddess of Power, Nayru, the Goddess of Wisdom, and Farore, the Goddess of Courage created the two realms of Hyrule and Termina.
Farore: Before they left the world, they left a gift in each realm; the Sacred Triangles. Hylians called theirs the Triforce, while the Terminans referred to theirs as the Triad.
Din: For many years, the two realms coexisted in one world. Two separate countries on a single planet. People were free to move between the two realms freely, and the two lands depended upon the other. Certain resources were plentiful in one land while other resources occupied the other.
Nayru: However, this harmony was not meant to last. A dark creature named Majora attempted to gain control of both realms. He used power, fame, and fortune to manipulate unsuspecting souls into doing his bidding. He also used macabre rituals to transfer his essence from his body into a sort of energy, which he hoped would prevent him from ever being killed.
Farore: Majora eventually targeted a young man named Nexus. He promised the man the power of a god in exchange for his help. Majora foresaw that Nexus would be "betrayed" by the Hylian king, and Majora goaded Nexus into channeling his anger to nearly obliterate the two realms.
Din: The survivors of the attack came after Majora and Nexus. Majora's body was mutilated by the angry mob, but his essence was transferred into a cursed mask that bore his likeness.
Nayru: Before the mob came for Nexus, he came to his senses and, while he was still angry, he was also disgusted with himself. He would have allowed the mob to kill him, but did not realize that Majora cursed him as well as endowing him with his gift; when his body was destroyed, his soul was also placed into the Fierce Deity's Mask.
Farore: The mask, when worn by a man of a virtuous heart, would spell doom for Majora and his fellow villains. But if it was worn by a man with an evil heart, it would aid them in destroying Hyrule and Termina.
Din: However, the mask would also impress upon its user Nexus' opposite personality. Meaning, if a righteous man wore it, they would also become a stronger and angrier person, and if the wicked wore it, they would begin to repent their ways.
Nayru: Soon after these events, the two masks were separated. The Fierce Deity Mask was sent to Termina in order to aid them, for no great heroes were ever prophesized to appear in that realm. Majora was left in Hyrule to be dealt with by the Hero of Time.
Farore: We then separated the two realms. A new planet was created in an alternate dimension, and Termina was sent there in order to ensure that Majora and Nexus did not meet again.
Din: Majora, however, somehow acquired the ability to traverse the two worlds.
Nayru: He planned to let Ganondorf take over Hyrule while he went to Termina, where there was no Hero of Time, and nearly destroy the realm and claim the Triad for himself.
Farore: The Hero of Time's presence in Termina was a surprise and a setback, but he did not fear death.
Din: Now, he is planning to ally himself with the great King of Evil in order to finally control Hyrule and the Triforce.
Nayru: Furthermore, the dimensions are beginning to reunite. The separation was never meant to be permanent. The two worlds were supposed to merge back together after the Hero of Time defeated Ganon in Hyrule and Majora in Termina. If this happens, with Ganondorf and Majora alive and at full strength, both realms will likely perish.
Farore: Fortunately for the inhabitants of Hyrule and Termina, there are two things that Majora doesn't know. One of them is that, allowing Nexus' spirit to survive would inadvertently create a second Hero as well as strengthen the prophesized Hero of Time. The other is that anything can be defeated.