Hakamori Tsuma to Ougon Ryuu: Hamerareta Hanayome desu ga, Gosenzo-sama ga Tasuketekureru You desu

I was lucky to marry the mysterious head of the Vernois Dukedom, but he is 80 years old, bedridden, unconscious, and cursed. It was clearly a political marriage, but my 66-year-old brother-in-law, who is acting as the head of the family, told me to "be the gravekeeper on my own." I was fed up with being treated like a servant, but my ancestor enshrined in the mausoleum was a golden dragon that produces gold mines. "I'll help you out of all the terrible things you've been through!" the golden dragon said arrogantly, but... A love(?) fantasy unfolds between the gravekeeper's wife, the golden dragon, and the mysterious head of the family. Source: MU