Birthday-Death Disease

Birthday Death Disease is a mysterious disease that occurs on the surface around the Abyss. A person falls horribly ill on their birthday, and by the end of the day they will have died, no matter what medical treatment they receive. The disease was thought to be a rumor, but presently, five people have died on their birthdays in a span of a few weeks. It is a subject of great worry for the citizens of Orth. The only survivor thus far is Kiyui, who recovered in mere minutes after he was taken out of the Abyss' vicinity onto a ship by Mio.

It is thought to be the cause of all the 2000 year old Praying Skeletons found around a burial tower in the 1st layer. Underneath this, there is another burial tower with even more praying skeletons, dating back 4000 years. And under that one there is yet another, this time with skeletons ranging to 6000 years old. Though the reason for these mass deaths is unclear, birthday-death disease seems to be a likely candidate. The cause of the disease is unknown, but is thought to be linked to the Abyss itself. Those who do not leave the Abyss when it goes around can only pray to be spared, thus the reason for the praying skeletons' positions.