Seelenstone

The Seelenstone was an artifact from Innistrad, that was worshiped in the Priory of the Approaches of Kessig.

Description
A white rock as large as a goose's egg, glowing with its own soft light. The light was a shifting, milky radiance, like the colors of oil on water. They spun in a serene pattern, as if the stone were filled with different iridescent liquids, flowing in an eternal circular procession.

History
The Seelenstone was granted to the Approachers by the Nameless Angel to fight the influence of the Bog. It was first given to a lone priest, who kept it in a shrine. Then a church was built for it, and the catacombs to house the dead. Finally, the prioress Merlinde came to build a full priory.

Villagers were proud of the relic, which stilled the souls of the church's followers, preventing them from rising as a geist or other foul creature. But it also prevented a soul from returning to the Bog. And so while the Approachers were proud of the Angel's blessing, most resisted conversion to the Church of Avacyn.

As a new acolyte at the Priory, Willia Verlasen had been guarding the Seelenstone during daytime. It began to speak to Willia and told her of power and that she could use it to stop the darkness. She just had to make it whole, by finding the other pieces scattered through the people of the Approaches. Each one with a little sliver of power. The first pieces Willia reclaimed were the souls of her parents. When she found that they were carrying offerings to the Bog — what she thought was a false god — they fell into an argument. She didn't mean to kill them. But the power from the stone, combined with her own, made it happen and turned them into Whisperers. After this, she had begun harvesting souls, killing the villagers and betraying the occupants of the church. By this time, the Bog Entity had gained the upper hand again and she was ready to kill her sister to make the Entity whole. The Seelenstone was of no consequence anymore, and she broke it to release its souls for the benefit of the Bog Entity.

Trivia

 * Seelen is a German word and is plural for Seele, meaning soul.
 * Dack Fayden once had planned to steal the Seelenstone.