Fire

Fire is not an element in the modern sense. It is a reaction. Fuel, oxidizer, and heat meet; bonds rearrange; energy is released as heat and light.

On the card Fire also holds the older use: transformation, Hearth, ordeal. Map items about combustion, ash, smoke, Lava, and ritual flame feed it. Glow is heat become light without needing its own type. Heat and Light take what is physically those things rather than the flame.