So how does building shrines work? It seems that in the computer game, you first have to sacrifice to learn a mystery and hope that it is a blessing suitable to be maintained by a shrine? Does that apply here? If so: are ancestor shrines the same? Is it a matter of knowing the mystery, and you can build the shrine years after the blessing itself has worn off, or do you have to build the shrine while the blessing is active, and how long do those last without being maintained by a shrine, anyway?