Guy Gardner and Joe Morgan were two men with good dispositions yet tragic circumstances that led them to oppose their respective world's Green Lantern, with power equaling theirs, twisted and torments but evil entities from beyond the stars.
Hal Jordan as Green Lantern saved school teacher Guy Gardner while Guy was himself saving a scared girl from the collapse of a bridge. Gardner developed a romantic relationship with Kari Limbo, one that would not last the test of time. Guy's forestalled career as Lantern's ended quickly in tragedy. Caught in a power battery discharge, Gardner was sent to the Phantom Zone, after which he was eventually freed and returned to Earth-One by Jordan. The experience left Guy mentally traumatized. Gardner would later be revived and then granted the power and title of a Green Lantern once more during the Crisis on Infinite Earths, given a mission to lead an army of super villains to the Anti-Matter Universe to defeat its leader the Anti-Monitor. The fact that Jordan had started dating Kari while Guy was in the Zone led to enmity between the two Lanterns that persisted for years. Joe Morgan was a former boxer turned professional trainer who had first groomed Ted Grant, then Al Pratt and... throughout the years off and on... Jim Harper. Each man was to be his legacy, yet each took this training and became the superheroes known as Wildcat, Atom and Guardian, respectively. Feeling jilted at their abandoning Joe and his aspirations for greatness, he was cornered in an alleyway by an entity composed of the evil intentions of the Guardians of the Universe that originated in Earth-One, a globe of power seeking to consume and merge with Morgan to become Evil. Together, they mentally manipulated his former students into attacking the globe's intended target, Alan Scott aka the Green Lantern of Earth-Two, alongside his allies Flash and Wonder Woman. After defeating the trio, the six heroes then split in pairs to each track down Morgan... or Nat Milligan as he was known to Harper. Bringing all three cloned bodies of Morgan to one location and merging them, Lantern unknowingly unleashed a powerful Evil against them all. Once they defeated him, their friend turned foe reverted back to Joe Morgan and perished, while the globe was exiled to space.
Alan Scott earlier had learned that his predecessor to the power battery, given to him by a monk, was a former businessman named Mister Billings. When the stock market crashed, Billings lost all his wealth and blamed his investor whom he slew. Incarcerated in Arkham Asylum in Gotham City, he was given the ancient Chinese lantern crafted by Chang from a Green Flame meteor. Refashioning is as a modern battery, it flamed and restored Billings sanity. He returned to his life among society.
Hal Jordan had himself not been the first Green Lantern of his earth, as his predecessor Abin Sur had previously bequeathed his power ring to Sheriff Daniel Young in 1873, as Young used his newfound weaponry to bring some criminals to justice while Sur was healing from injuries. Once Abin was revived, he reclaimed his devices while Young returned to his career as a local lawman.