Ze Arch is... Well. Its easier to explain with a passage from The Book of Curves.
In the book of turns, chapter 3, Jean Pierre LaBlanc said unto his flock;
"We shall all be raised up by the glory of Ze Arch! We shall be royal beings in its gaze, forever lifed up to the apex of the Holy Curve. Those that do not give themselves to its Holy Perfection, shall be brought down by the arch and smashed by the ends of mistrust and foolishness."