This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Zahhak (Persian)
Zahhak is described as a three-headed, six-eyed, dragon-like monster. He is said to have a thousand senses, and to bleed snakes, scorpions, and other venomous creatures. He also is said to bring or control storms and disease. His wings were said to be so enormous that they would block out the sun.
The dragon roamed through the universe until Angra Mainyu, perhaps regretting his decision to create such a monster, decided to end him. His champion Thraetaona or Feridun could not kill the dragon but chained him instead to Mount Damavand, where Dahak will have to remain for eternity. It is further prophesized that Azhi Dahaka will break free of this prison as part of the Zoroastrian apocalypse, and will kill one-third of humanity before finally being slain by Keresaspa.