While verse 4 is popularly believed to be a the Devil, it is actually referring to the antichrist, who was expected, came and hit the start button on the final hour:
KJV 1Jn 4:3 And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world. 1Jn 4:4 Ye are of God, little children, and have overcome them: because greater is he that is in you, than he that is in the world.
So is John suggesting that the antichrist was a particular homo-sapien male who appeared and his identity was known? Or any who oppose the apostolic teachings about Christ?