pyromancer

/ˈpaɪrəˌmænsər/
noun
  1. A person who practices pyromancy; a fortune-teller who uses fire.
    • The ancient pyromancer gazed into the flames to predict the harvest.
    • She consulted a pyromancer who read the shapes of the campfire's embers.
    • In the fantasy novel, the pyromancer summoned a wall of fire to protect the village.