The rarity of the patron saint of Nippolo is determined by its probability of appearing in the game. The patron saint of Japanese Totoro is a rare patron saint in metal gear's Phantom Pain game. Its appearance probability is relatively low, so it is considered as one of the rare patron saints.

I don't know much about how to get the patron saint of Japanese Totoro, because different games may have different ways to get it. Generally speaking, however, players can obtain rare patron saints by completing specific tasks, defeating specific enemies or exploring specific places.