Sparkit: Fox type stores electricity in its tail. Can use then sparks to cause fires. It's inexperienced at holding a charge however and is known to randomly discharge its power accidentally setting blazes.
Zapox: It's mastered holding a charge so can store more, its extremely long tail can hold large amounts of electric energy causing it sprakle. These sparks can easy set large fires quickly if it wishes.
Chargowl: it's learned to create electric sparks and fire at a whim by bristling it's coarse fur so no longer needs a tail to store energy. As a result it develops a short tail better for intense battling.