What kind of power brought those two natural enemies together?

I learned as a boy, government is the natural enemy of the people.

Every living thing has a natural enemy in its own environment.

Sometimes I think they are the natural enemies of women.

But there are ways to deal with the natural enemies of summer.

They are plants from other parts of the world, with no natural enemies here to control their growth.

Men start at the notion of a natural enemy, and ask no other question.

Now almost everyone has a certain "natural enemy" if I may call it that.

Had he given one of his natural enemies, an undergraduate, a hold over him?

They live well into their teens and have few natural enemies.