What drives Endo's fiction, and what he ignores

Having finished the Shusaku Endo story collection The Final Martyrs, which covers about 30 years of his writing life, a few salient facts strike me: It's amazing how he returns repeatedly to the same material, using the material, generally in new and surprising ways, in story after story and in at least one novel (Deep River, the only one of his I've read): lonely childhood in occupied Manchuria, parental divorce, life as a devout Catholic in part of a once-persecuted minority, survival of the war through the fighting in Burma (will come back to this in a moment), affection for dogs and birds, loss of faith especially among Catholic priests, group-tour travel to Europe (and India, in the novel), death of brother, illness and aging. And what doesn't he treat?: marriage (though his narrators are married and seem to have a comfortable relationship with spouse, the marriages always seem pallid and are never the central element in the stories), the war as experienced in Japan (one exception, which I'll come back to), war guilt (never even touched as a topic as far as I have read). His stories, also, come as close to autobiographical essays as any I've encountered; I'm guessing he takes some liberties with names, time sequences, and invents details when he cannot recall the facts precisely, but he could probably identify these many of these pieces as essays and be none the worse off. The last 3 stoires in the collection offer a few new insights into Endo's work. The story about an alcoholic man who reluctantly visits a psychiatrist and confesses that he ate human flesh to survive the war (a theme treated in greater detail in Deep River) has an explicit religious context: the title is The Last Supper, so how can we miss the reference to eating the body, that the consumption of human flesh in order to survive is like a communion, giving life (or eternal life, as the case may be). The last story in the collection, The Box, tells of the efforts of the Japanese government during the war to spy on a group of Catholics who may have been engaged in seeking a peaceful resolution; the story itself is full of improbabilities - the narrator finds a box containing a cache of documents from the era, leading him to draw conclusions about the wartime spying - but it's a unique story in Endo's work in that it takes on the brutality of the Japanese secret police, a topic he largely overlooks.