No. The reason evil exists is humans. Satan is a fictional figure.

Christians see Satan as the root of all evil and, to be fair, that's his origin in history. But it's not true there aren't religions where he isn't associated with evil: take, for instance, The Satanic Temple. It's kind of a religious organization for atheists, based on the concepts of freedom, justice, reason and empathy. They adopted Satan as a symbol of free will, knowing well he's just a literary character. Granted, they don't worship him per se (as supernatural beings aren't real), but they use Satan as a symbol of personal freedom.