"Suttree" doesn't come up as often as his other work but is my personal favorite. There are some darker moments but it's a very funny book - a lot of "Charles Portis"-esque conversations and encounters.
He’s the embodiment of a force that just overtops and envelops everything in its path. It’s doesn’t even make sense to consider him moral or immoral or amoral (as many do when considering him a stand in for the devil) but more as a force that just transcends morality completely and makes it irrelevant, a force that has no other purpose but to expand and consume resources, indifferent to death or convention or tradition. A force that never sleeps.
I think the scene where he calmly ignores the Indian attack while making explosives is probably the most literal example but the theme runs through his character.