What really happened to them after they faded will always be a mystery that may never get solved. But what happened to the Earth is up to the readers imagination. Maybe they all died out and civilization was rebuilt leaving a happily ever after.
Or maybe all the live humans and animals were all killed off, leaving the zombies to starve off leaving complete nothingness on the planet.
Maybe something escaped everything and everything started up again.
Nothing can truly be knowing because no more chapters will be written by this author. It's up to the minds of many to decide what could come next.
But one thing that we do know, even thought (in this story) the members of My Chemical Romance is gone forever, their memories will carry on...
Also to anyone who cried during the reading of this story, here I virtually send you a plate of your favorie cookies to make you feel better.