On their journey of resurrection, Dustyleaf and Dino need to face dark creatures that lie in the middle liers, which is the plain between Earth and the Moon Realm. In order to defeat this creature and escape the middle liers, you must face your problems head-on or continue to run from them, which only makes things worse. If they don't make it back to Earth before the next sunset, they die, and perminately stay in the Moon Realm. (Thus the reason they look a little faded)