Magma Vein was once human given a chance to work as a guard in hell. Strings attached? Not so many surprisingly. He serves as a warden of the infamous prison, keeping the inmates from escaping and stopping outsiders from helping them. A week after reaching the highest rank of the wardens, the 'Guardian of Hell', a new creature emerges, claiming to be the Spirit of Chaos. Next thing Magma knows he's in a hot tub with a certain princess.
What does the stranger want with him? Why is he a pony? What the hell is a cutie mark? Can he still use his powers? How can he get back home? ... Does he even want to go home?
Image by the wonderfully talented Huussii of deviant art: http://huussii.deviantart.com/ Note my character is inspired by his flaming skeletal design but will have different features.
We all have our opinions of the afterlife, if one exists. That's not the main focus of the story. It's what happens when a demon crosses over from Hell. A little tinkering around with the idea of what happens in hell... well for the monsters anyway.