The Exiled Demon Lord Heads to Earth!

The Demon Lord was purged from the demon race and sealed away by the Hero, but an eternity has elapsed and she has finally been revived! She awakens in a wasteland, with stars twinkling in the pitch-dark sky, the air feeling somewhat thin, and somehow her body feeling light... When she regains her composure and searches for any sign of the Hero, she finds he seems to be on a faraway blue planet in the sky...? She doesn't know where she is, but putting that aside, the Demon Lord will make strenuo...