From what we’ve gathered, Joules seem to be the purest essence of Anèria — the land of the Kaiju. They hold latent energy, ready to be released, but for too long concealed by stagnation.
When you collect a Joule, you hold a key to reanimating Anèria and saving it from the looming darkness. It’s pretty bad — trust.
A word to the wise, though. When you come into contact with a Joule, things… change. You might be referred to as a “Kaijin” or a “mysterious person.”