She was a divine. Devine even among her own kind.
And he and his subjects were from the underworld. The mistake of a planet. The single blemish in the entire cosmos. Frowned upon by the divine, from their place in the sky.
But he was royalty and that couldn't be argued. And careful to not disrespect him, the divine invited him to festivities.
It was there, he got close enough her, the petite, silver haired maiden that he always admired from afar. "Serenity" he whispered. "Visit earth" he suggested, before leaving the party.
Serenity was delighted with the offer. She knew, no matter the risk, she would end up going.
That night, she slipped away from her guards and found her way to the earth.
After walking the earth, she found the Prince, sitting in the gardens. She admired everything about Earth, and asked about everything. Time passed, and she was forced to retreat home. But she came back time and time again for months. And the two fell in love.
Then Serenity turned eighteen. "Here eat this." Endymion told Serenity, while handing her a round object. "It's a pomegranate. It's used to propose. It's official only when consumed at the altar." Serenity jumped up and hugged him.
A cry of outrage was heard throughout the Galaxy. Serenity's divine friends listened as their royal parents bickered. It was going to turn into a full blown riot once Serenity returned. Which was, incidentally, soon. By her will or the Queens. But the tradition was set. And the Earth King and Queen insisted the vows and tradition be honored. Queen Serenity argued that the Moon needed an heir.
Although neither kingdom was pleased, the ruling was Serenity was to spend every other month on the Moon. And the other months were going to be spent with Endymion.
When the couple presented themselves to the Lunar court, to be married again by Lunar traditions, standing in the sidelines were Serenity's guard and friends. The leader, a descendent of Aphrodite, stepped into the spirit realm as Serenity passed. From her sight, the couple had a thin red line of string connecting the two. She smiled secretly as others looked at her funny.