Stanism is presumably either a misspelling of "Satanist", or treating people with the given name of "Stan" as Gods among men.
The Stanist religion is a three person cult centred in Massachusetts. Its primary beliefs involve an almighty creator whose name is Stan, and eats planets. His wrath can be assuaged by holding aloft his holy symbol, an empty bottle of chocolate milk (Only Byrne Dairy brand is acceptable, any other form of chocolate beverage would be blasphemous, with punishments including death by chocolate frog.)
During a holy war, there is but one weapon that is truly righteous enough for a Stanist soldier: a three foot long Byrne Dairy chocolate milk bottle, still full of the Holy Milk. Once an enemy of Stan is defeated, they must be smited over the head with the holy weapon, in order to purge them of evil and set them upon the Righteous Path of Stan.
There is one enemy of Stan who is truly the embodiment of all that stands against his chocolate milkiness, and is therefore his arch nemesis. His name is Nats.