File:Recurring stone tablet.png

Summary
These stone tablets appeared in the anime almost exactly 4 years apart, with the one on the left featuring in ' and the one on the right appearing in '.

Both tablets were discovered by archaeologists amongst ancient ruins. The first by Dr. in the ruins of and the second by  amongst the.

The tablet to the left apparently contains the legend of while the tablet to the right contains instructions on how to enter the stone chamber of the.