The dragon is meant to 'harvest' electricity through its tail in its body. It can use this saved energy to attack other creatures or just for the fun of doing so.
Also I tried to approach an unusual design for the wings, though I'm not sure yet if it works. Because the wings need to stand the strong winds of a storm, I thought of giving two arms for each wing- the back one will be probably much more slender than the other one, because it's just for stabilizing the dragon.
The dragon has no other arms/legs, so usually it would live in the air (preferably a storm) or in the water.