Looking at Signorelli’s Rule of the Antichrist, we see the signs he is not the real deal; for despite superficially looking very much like Jesus and despite his performing miracles right in front of our eyes, such as raising the dead, we see in Orvieto a terrifying horned Satan whispering in the fake messiah’s ears. He isn't just telling him what to say either, for his left hand is slipped into the sleeve of the antichrist's rosey robes, like a puppet master calling all the shots.
Worse still, behind the adoring crowds, his black armies are re-taking the Third Temple. Some have suggested the Signorelli’s antichrist was the heretical priest Girolamo Savonarola, only recently burnt at the stake in Florence for just such apocalyptic fear mongering. Many at the time considered him to be a saint. The Pope begged to disagree.