Mahadev is a composite god. He is both Destroyer and Creator, at once the end of things and the beginning of the new ones. Terrible, he is Bhairav (The Cruel)or Rudra or Ugra or Shava (The Corpse). Peaceful he is Mahadeva (The Great God) or Ishwara(The Lord)or Pashupati (The Lord of the Beasts)