I never did tell that story. The Soultrap Cube is an ancient Moonshadow myth, but perhaps you have similar in your myths as well.

Once upon a time, a brave Moonshadow hero named Salyas climbed the darkest mountain in all of Xadia and begged the Moon for its greatest gift. The Moon asked her what she would use it for, and Salyas replied, “I won’t use it. I only wish to lead my people well. Such a boon from your Mystery would show them that I am blessed with your favor, and in unity we can prevail.”

The Moon decided to test the elf, so it told her that it could give her what she asked for, but that this gift would also contain the Moon’s deadliest curse.

Salyas agreed, passing the test, and the Moon gifted her a bright white cube. It told her never to open it, and she swore an oath to guard it.

She led the Moonshadows for a hundred years of peace and prosperity. But as she lay upon her deathbed, her son sought a way to extend her life and the peace that she had brought to her people. He slid open the tiniest crack on the lid of the cube, and he begged it to save his mother from death.

A soft voice hissed back to him. “Let me out, and I will ensure that your mother never dies.”

“Never? Do you swear it?” the loyal son demanded.

“Never. Open the cube and leave, and I will do my work.”

So the son left, and as he stepped outside, he heard a soft slithering noise behind him. But true to his word, he did not turn around.

The next morning, his mother’s husk was found shambling through the forest toward the black mountain. Horrified, her son rushed to the cube and found it shut. Showing a bit of wisdom, he dared not open it again.

When Salyas’s husk reached the black mountain, the great rise of stone crumbled to sand, covering the forest for dozens of miles in every direction and freeing all the soulfang serpents that had been imprisoned inside it.

In horror at the loss of so many villages destroyed in one night by the sudden desert, and at the release of a deadly new creature into the world, the new Moonshadow leader bound the Soultrap Cube away at the last remaining bit of forest to survive the Midnight Desert: the oasis. The cube’s pull draws the serpents to it, but the Wonderwall keeps them at bay, binding them to wander the desert, ever unsatisfied. As do the husks of the unfortunate, led by Salyas in an ever swirling pilgrimage that cannot approach the oasis either.

One last thing remains inside the Soultrap Cube, and it must never be opened again, nor must the soulfangs or the husks ever find it, lest either of them consume it and leave the world lost.

What lies within the cube? What is it that must be protected from good and evil alike?

That depends on who you ask.