Chapter 373 is the fifth part of the "Nightmare Arc".
Nenomious continues to take care of Nastasha and live life normally. Seasons pass like this. After 12 years, he goes into town to buy things. He is questioned on his ageless appearance.This sends him into a state of panic. He runs off to his house and looks at Nastasha then himself in a mirror. He realizes the truth of the villager's observations and curses Arumio.