The Hiisi will typically attack all other enemies, but will not attack other Hiisi. Tulihiisi use their fire immunity to stay alive while throwing cocktails that spill Liquid Fire everywhere, creating an inferno. While they will not throw them at other Hiisi, the rapidly spreading burning liquid makes friendly fire common.
The Cocktail Flasks it throws are a special type of flasks. As with the flasks thrown by Alkemisti, they can be caught in mid-air or may land softly (in a liquid pool, for example).
These cocktail flasks cannot be refilled. They will explode if thrown, even if empty.