Originally Posted by JandK
I don't think Shar wants to end the universe. I'm not sure where that's coming from.

The following excerpt is from Faiths & Avatars ->

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Chauntea begged for warmth so that she could nurture life and living creatures upon the planets that were her body and limbs, and the two Sisters-Who-Were-One became divided, as for the first time they were of two minds. Silvery Selune contested with her dark sister over whether or not to bring further life to the worlds. During this great conflagration, the gods of war, disease, murder, and death, among others, were created from residues of the deific battle. At one point during the battle, Selune seized the advantage and reached across time and space to a land of eternal fire. Fighting the pain of the blaze, which burned her sorely, she broke off a fragment of that ever-living flame and ignited one of the heavenly bodies so that it burned in the sky and warmed Chauntea.

Incensed, Shar redoubled her attack on her injured twin and began to snuff out all light and heat throughout the crystal sphere. Again Selune gave of herself and tore the divine essence of magic from her body, flinging it desperately at her sister in defense of life in the sphere and nearly killing herself of the spiritual injury it caused her. A just-born being of raw magic tore through Shar, bonding to some of her divine magical energy and ripping it free of her, and reforming behind her as the goddess of magic, known now as Mystra, but then as Mystryl. Though Mystryl was composed of both light and dark magic, she favored her first mother Selune initially, allowing the silver goddess to win an uneasy truce with her more powerful, dark twin. Consumed by bitterness at her defeat, Shar vowed eternal revenge.

Essentially, she prefers an unending expanse of cold darkness bereft of life.