Reign of the Superman - Secret Origin of the Ultra-Humanite?

In 1933, a chemist procured a meteorite, from which he extracted a unique element distilled into an experimental portion. This man, Professor Ernest Smalley, hypothesized that this potion could grant a human tremendous mental abilities. Seeking a test subject, Smalley found the ideal candidate in a bread line...a vagrant named Bill Dunn. 

And indeed, Dunn gained the power of telepathy, mind-control and enhanced vision. However, a side effect of this potion turned the normally good natured Dunn into an evil megalomaniac. Slaying Smalley, Dunn enacts a sinister scheme to rule the world, until the effects of the potion begin to wear off. Dunn believed that within a short time, he would lose these tremendous gifts. 

While “Bill Dunn” never reappeared, another supervillain from the same era rose to prominence, one with vast intellect he seemed to acquire due to a scientific procedure. In the decades to follow, this sinister scientist manifested mental might equal to his world’s most powerful telepath, even challenging that man… Brain Wave… into a battle of the mind he ultimately won.

So what if, while unable to read minds as before, Dunn still retained some of the other skills? What if it continued to corrupt him? What if his legend grew over time, under a different alias?

Indeed, six years later in 1939, a man whose appearance quite resembled Dunn began terrorizing the Metropolis of Earth-Two. This criminal mastermind, identifying himself as the Ultra-Humanite, had repeated clashes with the new hero known as Superman. In fact, when these two titans met, Ultra recalled how a scientific experiment granted him an agile and learned mind! Was the meteorite Smalley used Kryptonite? Could Dunn have been one-in-the-same as the Ultra-Humanite*?

In fact, Ultra's story mirrors that of another amazing mind, the android known as Brainiac. On planet Colu-One, the robotic overlords of that world implanted the mental pattern of a humanoid scientist into Brainiac's mind. This android would be a recurring adversary of the Superman of Earth-One. And like human turned automaton Brainiac, Ultra sought an artificial body when he once attempted transplanting his mind into the metallic frame of Robotman. Ultimately, the Humanite became a super-simian instead.

* The creators of Bill Dunn in the 1933 tale “Reign of Superman”, Jerry Siegel and Joe Schuster, were also the creators of the Ultra-Humanite in 1939.