Gray is the feared, mystical woman that inhabits Temple Sedulous. She appears to have the ability to transform into a giant, gray bat. Other powers of her include the power to compel and immobilize foes with an ear piercing screech.
Those that seek her out usually do so in order to drink of her saliva, the only known cure for a bite from the Moon Bats of the Easterly Plains bat.
Dr. Owen Mason sought her out for this purpose and was also able to destroy her in the process.