EXACTLY LIKE IDEK HOW TO STOP I
SPOILERS!
You don't want me to spoil the game, do you?
YOU BETTER HAVE COMPLETED THE GAME!
Okay, here it is :3
Go into the forest, then talk to Thunder, and then click on the fire cats to fight them! (They are in all the seperate forest areas!)
To stop it you must go to the forest (If you have the map from the med cat) and talk to the guardian there, afterwords you should start seeing fire shaped like cats and all you have to do is defeat them in a fight!