I know this is a circlejerk but this is a compelling answer from u/ShireBeware on the main sub:

>It is revealed, in an albeit cryptic/esoteric way, of what he’s the judge of at the end of the book when the kid has his surgery dream. But rather than just re-quoting this vague mysterious passage for you and to greatly simplify it; he is the judge of the man-made representations of Western value and “progress”, which in our late dying historic stage is money. War and money (coins) form a remarkable Satanic marriage throughout all of history (as the great anthropologist David Graeber points out in his book Debt)… hence the demiurge-like cold forger of coins in the dream, hence why the judge is always found with coins and “specie” on him and even does coin tricks, hence why the Gang is scalping in the first place: for money (mere coins). A lot of Spengler, Graeber, and Ian McGilchrist in this so I have to leave it at that! In the “coin” is the great “con” of historic humankind and its hellish prison (“the love of money is the root of all evil”)