I'm telling a story set mainly in the Underworld, set in many dimensions. The main character is essentially Death, and he finds out that the Gods want to destroy Earth. This is a problem for him because while he feeds off death, he needs people alive to keep dying if that makes sense. But to these gods, Earth means no more to them than Ants do to humans. I need some ideas and pointers for something that could cause them want to end the planet. Any guesses?