Shar

Shar, the Mistress of the Night, was the chaotic evil goddess of darkness and the caverns of Aletrias. Counterpart to her twin Selûne, she presided over caverns, darkness, dungeons, forgetfulness, loss, night, secrets, and the Underdark. Among her array of twisted powers was the ability to see everything that lay or happened in the dark. Shar's symbol was a black disk with a deep purple border. Titles afforded to her included The Nightsister, The Veilweaver and the Shadowcaster. Spiders were her favoured creatures.

"Blessed Nightsinger, witness our adoration. See how we serve you, only you. We have emptied our hearts of falsehoods. We have vanquished your foes. In darkness, we see your truth. Embrace us, your loyal warriors. Cloak us in your shadow. Guide us to your victory. Shar's will shall be done. As sure as night will fall.”

— Shadowheart's prayer to Shar

Divine Realm
Shar's realm was the Shadowfell, a dark mirror to the Feywild. A bleak and desolate place, it was to a remote corner of the realm that Barovia vanished in 187 of the Fourth Age after Erebus Krais made a vow with the dark powers to become the first true vampire.

Description
It is said, long ago that Shar and Selune were the ‘Sisters-Who-Were-One’. Two aspects conjoined, but by her nature, Shar could not be contained. An agent of lies and trickery Shar is able to topple empires with words and drives even the most learned sages to madness. Empress of the Shadowfell, Shar appears to mortals as whatever they most desire, for her art is to bend shadow to her will and cloak herself in ambition and desire. Formless and in all darkness she is immensely powerful and despises her sister.

Worshipers

 * Main article: Cult of Shar

The clergy of Shar were a secretive organization that pursued subversive tactics rather than direct confrontation with its rivals. In addition to her clerics, Shar maintained an elite order of sorcerer monks who could tap Shar's Shadow Weave.