Who created evil spirits?

Good question. Depends on how you look at it. I think that God created all the spirits, and that he also gave them choices... some of them chose to be evil. I don't think that any spirit was created evil. Isaiah 45:7 I form the light, and create darkness: I make peace, and create evil: I the LORD do all these things. 1 Samuel 16:23 And it came to pass, when the evil spirit from God was upon Saul, that David took an harp, and played with his hand: so Saul was refreshed, and was well, and the evil spirit departed from him. 1 Samuel 18:10 And it came to pass on the morrow, that the evil spirit from God came upon Saul, and he prophesied in the midst of the house: and David played with his hand, as at other times: and there was a javelin in Saul's hand. 1 Samuel 19:9 And the evil spirit from the LORD was upon Saul, as he sat in his house with his javelin in his hand: and David played with his hand.