Mist

Mist was a heavenly person found by Freyja and used as Freyja's experiment because of her strong power. Freyja tested on Mist and conducted various experiments. Freyja was unsuccessful because Mist's shackles couldn't be controlled as Her mind was too powerful. Mist became too dangerous so Freyja imprisoned her in the depths of the heavenly realm. Eventually, Mist became more mentally stable but her emotions all gone. Now all she could think was killing her foes. At Freyja's orders, Mist became her puppet and Freyja used her to wipe out strong enemies for her. Mist was giving a final and extra position among the celestial guardians, the eight seat. Mist once entered the battlefield with mist all around her and she was then called Mist of the Battlefield by the others. It is also revealed that Mist's spirit was actually a female celestial monk named Xuanzang. She was a friend of Sun Wukong before he was exiled from the heavens.