What state is fire?
Fire is an oxidizing chemical reaction that releases heat and light. The actual flames that you see moving and glowing when something is burning are simply gas that is still reacting and giving off light. Plasmas are gases in which a good fraction of the molecules are ionize
The state of fire is like explaining the state of ice water. which contain both water and ice. So the state of fire is a combination of #ionised gas -plasma# state.
Fire is a form of energy. I guess it can't be explained in the three states.