The First Sin
In the first days of humanity when the first man and woman were created, the archangel known as the Morning Star or Luciferum didn’t like how human souls were made the same as God’s, how God treasured them, and how He allowed them to go between Heaven and Terra so he devised a plan to make God hate them. There was a waterfall that bestowed powers and knowledge like ones that God had so Luciferum took them to this location and told them to be washed in it and they did so, not knowing what they were doing. When God caught them, He punished what was one of His best friends by creating a dimensional where he will punish those who are sinful like him from then until the final day. A third of the angels who thought like him were instantly sent here as well as Luciferum. As for the first man and woman, He allowed them to be able to be as smart as Him but they were not allowed keep the powers of God and not allowed to go into Heaven without first dying the first death of forsaking weak human nature then dying naturally through the body. The waterfall was then turned into a River of Lava and the land surrounding it became the Land of Decay.