Evil exists as a concrete entity, a creation of God, a word with a meaning, a word that has been brought to life through the Word, who is Jesus Christ.
I reject the existence of an all-powerful and all-knowing god if it means abandoning human free will. But does rejecting the god of supernatural theism require the rejection of the reality of god in its entirety? No. But it does require a different understanding of the reality of god and the characteristics of omnipotence and omniscience.