There were once two lost souls, completing each other.
The first soul was a gentle spirit, one of warmth and trust, as gentle as the wind of dawn spreading love around the world.
The second soul was harsher and colder but as caring as the first, its sharp dusk mind dictating order and balance around the world.
To humans, their purpose was night and day, yet they formed a perfect equinox, completing each other.
Despite their shared link, their divinity was imperfect, merely fragments from a species of another world. The two souls didn't falter, however, and kept looking for purpose as they aided each other.
When humanity stepped within the mirror of their home for the first time, the two souls stood ready, watching over the civilization that birthed them without knowing.
They gave them justice, assisting the construction of a fair empire. They gave them love, the means to care for each other and build something bigger than their own selves.
Yet, no matter how much they gave, no matter how much humanity gave back, the two souls still felt hollow, as if their understanding of their children was incomplete, impossible to fully grasp.
For years, the two souls kept watching over them, never leaving each other's side. The equinox was perpetual, and below it, mankind developed its strengths and flaws as their understanding of the anomalous kept growing.
One day, however, the dawn was desecrated. With the ultimate sin, the first break of sacred love, the equinox was broken. Dusk was enraged, the loss of his cherished half breaking the fragile bond it held with mankind.
Its justice was blind, and in its quest to bring back order, to erase the violation of its own justice, it destroyed much of what the two souls built together.
Humanity was whole and paid the price of the sins a mere fraction of it committed. All civilizations of the time remember a time of darkness, when the world they started to understand turned unknown once more.
Yet, out of the newfound chaos, few realized the birth of a much more cunning anger, one birthed from pain and grief, from the broken, violated soul.
Everlasting, the lost shards hunted the unclean, tormenting those who replicated signs that led to the ultimate sins.
One life after the other, their hunger for justice kept growing, insatiable. Despite eons passing, they remained shackled within the physical realm, stuck between reality and the blessed sleep, unable to move on.
Beware of the Lemures, the everlasting anger that emerged from the original betrayal. Cunning and omniscient, they will know of each sin, each dark thought from the mind of the unclean.