C.M.B.

We all know that a lot of the booty of the golden age of explorations made it into museums. The British Museum in the C.M.B. story, which had custody of the recondite scientific curiosities and artifacts collected by explorer/adventurers and stored in a Wunderkammer, decided to study the dusty arcana in the 19th century. Three investigators dubbed the "Magi" were appointed to do the research, each given a ring embossed with the letters C.M.B.

Fast-forward to present-day Japan where Sakaki Shinra is the curator of a museum of oddities. He now has possession of the C.M.B. rings, indicating that he has been granted the status of guardian of knowledge like the Magi that preceded him.