Is there a Japanese proverb that has the same meaning of this?

In my country, we do have a saying “There are serpents in every forest”, means there’s bad in good, something like yin and yang concept, but more focused on the negative side.

Now I wonder if there are Japanese mottos, proverbs or sayings that has a concept close to this one.

https://www.reddit.com/r/japan/comments/xczyv5/is_there_a_japanese_proverb_that_has_the_same/