When the guardian died, of course, he went to heaven. But heaven was not as he left it. In his absence with no guardian, the Snail Devil used the opportunity to deport the worst of his abysmal residents across purgatory and up on high.
Among them was Tony "Scarstalks" Mudsnail, a small time criminal who was about to make it big. Meeting a great grey slug from the mucus smuggling racket (who had died and simply wandered into heaven with several other snot dealers during the guardian's absence), Tony was hired outright to assassinate another high limax who had pestered the smuggler back on Earth. With that murder, Tony was in.
Soon, heaven was slick with stolen snot. The clouds dripped with Arizona Ariolimax, Panama Pustulence, Hawaiian Heave, and their most profitable import, Bolivian Booger (88% pure). Tony quickly tired of the old man's rule and killed him as well, taking over his empire and expanding into Snirvana and Snailysium.
But he had made too many enemies on his rise to the top. It was Alejandro Musa, the infamous Banana slug who would be his undoing when Tony became enraged and tried to drown him in his own secretions. Musa declared war and the great boss's army destroyed half Tony's mansion taking him down.
The guardian returned to see Heaven saturated in evil and began the long and difficult process of cleaning house. A fine job he did, but the holy kingdom never truly went back to the way it was. It was ever after just a bit less innocent.