Saint Oniisan is slice-of-life, or divine-life, tale of Jesus and Buddha as they try to experience the modern world: in this case, Japan. The manga places a funny twist on religion, attitudes, culture and customs in Japan through the eyes of Jesus and Buddha.
You see Jesus and Buddha experiencing Asakusa, public baths, theme parks, and the internet. Throughout the manga, we get a little history of their divine greatness only to see their apparent insignificance in modern Japanese society. Suffice to say, before people can recognize that they’re actually Jesus and Buddha, people think of them as someone who looks like Johnny Depp or a guy with a button on his forehead. For real.