What is the nine-year-old story about the Sai portrait mentioned in the text?

Chapter 41 reveals a story that took nine years to be fully told. The narrator and a priest named Ismu had made a private, firm determination that a 'portrait of the powerful Sai' should be kept in a specific place. The narrator presented the image, but because the recipient's meal was ready, there was no time to explain the long history behind this decision. The narrator intended to tell the story 'later at leisure,' but nine years passed before an unexpected meeting finally provided the opportunity. This reunion, where another 'wonderful dream' was also shared, allowed the narrator to finally recount the past history, connecting the extraordinary stories after a long delay.