Nemeses

Her lack of self-control when it came to spending was her financial nemeses.

The hero and villain in the action movie were nemeses.

The hiker's nemeses, blisters on her feet, made it difficult for her to continue on the trail.

The detective and his nemeses engaged in a cat-and-mouse game that lasted for years.

The nemeses of the detective were always trying to outsmart him.

The hiker's nemeses were the difficult terrain and bad weather.