Lets go with the idea that the ubermensch will appear.

Nietzsche said that if you were to meet an ubermensch you would not recognize them and think that they were a Devil. If they exist in society now, do you think that they're going to act like some big titanic Greek statue with a halo of genius emanating from shining white eyes with evil amoral hordes crushing everything in their path to ultimate power?

No, they're going to make fun of humans to themselves, and gain power by catering to all of the weaknesses that humans adore. All of the human neuroses, fear of death, hatred of life, celebration of weakness...it'll come pouring out of their mouths like a river to those around them. The ubermenschen in human society will disguise themselves as mere humans to avoid being destroyed by those who fear them, and may even be content in this role, as it is indeed a decent challenge to not be killed by groups of humans when they perceive something more powerful than themselves.

Clark Kent is Superman's comment on humanity, not who he truly is.