Rick Riordan said this quote
“ I will see you again,’ Hades promised. ‘I will prepare a room for you at the palace in case you do not survive. Perhaps your chambers would look good decorated with the skulls of monks.’ ‘Now I can’t tell if you’re joking.’ Hades’s eyes glittered as his form began to fade. ‘Then perhaps we are alike in some important ways.’ The god vanished. ”