Das Rheingold (ラインの黄金, Rain no Ōgon?) is an unending mountain of treasure that Siegfried gained from defeating Fafnir. Siegfried claims the amount was exaggerated, but says there was a large amount left even by the time his great-grandson was an old man. It is accidentally summoned in the Grand Orders after the summoned Fafnir is resurrected, so he asks the Protagonist to help him find it to keep it from being found by someone else. If the treasure is allowed to flow freely, the humans who find it will become prisoners of the great wealth, eventually causing much destruction as the country is filled with betrayal and distrust.