Nemeses

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

His phobia of heights was one of his nemeses that prevented him from enjoying outdoor activities.

The roadrunner and coyote were nemeses in the cartoon.

The cat and mouse were nemeses in the classic cartoon.

The thief's greed eventually became his nemeses and led to his capture.

The two rival gangs were nemeses in the crime world.