(Spoilers for Sister of the South)
The chapel is where the Sister of the South was hidden and the chapel is wear Endon and Jarred’s friendship was broken. I had always felt a little troubled why Endon would so easily believe Jarred would attempt to kill him, even despite his reliance on Prandine’s word. But after reading SotS I realise Endon had spent that entire night in despair, not only his parents’ deaths but the horrible weight of the Sister weighing on him. If the Sister could affect Lief enough to want to get rid of the belt which had been his life’s mission, it surely had seeped into Endon’s mind. He was already so hopeless and filled with despair, what was one more loss on top of the ones he’d faced already, so he accepted that his best friend could betray him too.
