Yuanshi Tianzun
A Taoist title of Heidi is the "Dark (or Mysterious) Heavenly Highest Deity" (). According to a myth, during the fall of the Shang the Demon King ravaged the world, so that Yuanshi Tianzun ordered the Jade Emperor to appoint Heidi as the commander of twelve heavenly legions to fight this evil. Heidi defeated the Demon King and was subsequently granted the title of Mysterious Heavenly Highest Deity. In temples dedicated to him, the bronze tortoise and serpent under the feet of his image signify that the good always prevails over evil.