In the 1st Layer, 300 meters from the surface, there is a burial tower where hundreds of 2000 year old skeletons lie with their hands clasped in prayer. Under the burial tower is another ruin with more praying skeletons, except these are 4000 years old. And even still, underneath that ruin is another, this time with skeletons 6000 years old. The cause for this cycle of mass deaths is currently unknown.
One theory stated by Ozen is that the praying skeletons were victims of the "birthday-death disease," a condition where someone inexplicably falls very ill on their birthday, and later dies. The cause for this is unknown, but is thought to be linked to the Abyss itself. It is a subject of much worry in Orth, as another 2000 years have passed and the mysterious disease is making its rounds once again, having already claimed the lives of 5 people. The only way to escape the disease is to leave the vicinity of The Abyss entirely. Those who cling to it can only pray, hence the position of the praying skeletons.
- Volume 6 chapter extras