Eclipso was sort of DC's version the Hulk, playing on the Jekyll and Hyde motif: good guy scientist who turns into a menace. In Eclipso's case all it takes is an eclipse to turn scientist Bruce Gordon into the villain Eclipso. Unlike the Hulk, Eclipso got to wear a costume, had incredible intellect and was an out and out villain. Gordon spent most of his time trying, and failing, to prevent coming into eclipses and then helping to set things up that would force him to become Gordon again. In this he is aided by his girlfriend Mona and her father Professor Bennet. A strong sudden light is enough to banish Eclipso.
Prince Ra-Man is a bit tougher to explain. He has his roots in an earlier strip featuring Mark Merlin who was an occult detective. He got himself stuck in another dimension and the only way to get back to our reality was to be cast into a recently deceased body. In this new body, he has various mental powers (telekinesis, illusion casting) and a powerful artifact, the six-sided sun. Sort of like the cinema version of Doctor Strange, it has the all of the earmarks of being a mystical hero but explaining it in pseudo science fiction terms while hedging their bets by also sprinkling in Egyptian references. Upon arriving back in this reality he tells Mark's fiance Elsa that Mark is dead. But, she travels with Prince Ra-man in his crusade against crime. Prince Ra-Man may be DC's first superhero to actually sport a beard. With that, plus a white streak in his black hair and his eyes being all white and black ringed, he is looking almost more like a villain than a hero at the time.
This story starts with Bruce, Mona and Professor Bennet preparing for the next eclipse and a plan to instantly banish Eclipso. As usual Eclipso uses his intellect to outwit them and embark on his next plan of world conquest. In this instance, Eclipso emerges from Bruce Gordon as opposed to Bruce transforming into Eclipso. Eclipso's plan involves him to create Helio, a being made from sun and various chemicals. He even designed a costume for Helio. Of course, it means Eclipso has to shield himself from his own being in order to avoid getting banished. With Helio's power, they steal a space platform so that they can attack anywhere on earth from the safety of space. Eclipso is eventually defeated and returns to Gordon's body. However, Helio is still out there.
In the part two, Prince Ra-man sets out to end the ongoing threat of Helio. In their first encounter Helio almost manages to kill Ra-man and Elsa in a cave in. Helio travels to the lab complex of Buce Gordon in Solar City. He creates an artificial eclipse which transforms Bruce into Eclipso this time. When Prince Ra-man arrives, he quickly reasons that Eclipso is Gordon's other self which Professor Bennet admits. The professor tells him this transformation is only temporary but if there is a real eclipse, Eclipso will split off permanently and if Eclipso and Helio are able to get the stolen space platform into space, they will be nearly unstoppable. Ra-man grows his disc to giant size and flies it like a flying carpet after the platform where he has to battle the two villains.
GCD lists both parts of the story to be by Bob Haney while Jack Sparling did the art for the first half and Bernard Bailey on the second. It's not quite the book length battle promised on the cover, it is still a fun read of a couple of off-beat characters. The stories don't give much background on the characters and so the handling of Eclipso seems a bit inconsistent, with him emerging from Bruce in the front half and a transformed Bruce Gordon in the second. Eclipso's appearances after his run were sporadic in the 1970s. Some reprints, a battle against Batman, the Metal Men, an appearance in Crisis. It would be in the 1990s that Eclipso would get upgraded into a major villainous threat as he was portrayed as a dark villain that was able to use his black diamonds to create dark-sides of the various heroes. In one issue of his own comic he would be responsible for the deaths of various characters including the original Steel, the lady Dr. Midnight and Wildcat, Peacemaker, Mark Shaw Manhunter, the Creeper and another or two. The Creeper would get better and the Manhunter killed was retconned to have been someone else in his costume. In these stories, Eclipso doesn't display the scientific expertise and cunning that he does in these Silver-Age stories where he seems more of a Doctor Doom or Lex Luthor style villain. Prince Ra-Man would cross swords again with Eclipso a few issues later. He would eventually come clean with Elsa over his identity. Not much later he was killed in the final issue of Crisis on Infinite Earths. Since then, there have apparently been sporadic inconsistent appearances of him and/or Mark Merlin.
