Hank Henshaw, a brilliant scientist at the time, and three of his friends were returning from space when they encountered a freak radiation storm. The radiation affected the machinery of the vessel and the shuttle crash landed somewhere far away from its intended target.
When the four explorers had freed themselves from the wreckage, Hank discovered that his friends Steve and Jim had been horribly transformed. Steve had become living radiation and Jim's body had been destroyed and reformed out of debris from the ship and the surrounding area. Hank's wife Terri seemed to be fine, but Hank himself could feel radiation sickness beginning to eat away at him.
The group went to Metropolis in search of a LexCorp facility that they could use to fix their mutations but ran into Superman and were subsequently involved in a time consuming fight. Things were worked out but by then the radiation's affects on Hank had begun to show. His flesh was falling off his bones and he was obviously close to death.
Terri also started exhibiting symptoms, beginning to fade from existence. Hank tried his hardest to work on a cure for her but he was going fast. While he worked, Steve flew into the sun and Jim killed himself. Hank came up with a plan to fix Terri, but died before he could use it. Thankfully, Superman was still there and he was able to save Terri before she completely disappeared.
Some time later, Hank returned in a new form. When his physical body had died, his consciousness had been turned to energy and sent into the machine on which he had been working.
Somehow he had gained control over the machinery and was able to form it into a robotic body he could use as transport. His first thoughts once reconstituted were of his wife Terri who had been institutionalized after the traumatic events which he had witnessed.
Henshaw found Terri but after appearing as a robot and leaving suddenly when security came, Terri was left even more disturbed than before. When Henshaw heard how his visit had made Terri feel, he decided it would be best for him to leave Earth and continue his hunt for knowledge on his own.
Henshaw found his way to Superman's birthing matrix and made it his new body so he could travel space again, absorbing the knowledge of the universe in the process. Superman found him and tried to stop him, but Hank flew away.
Cyborg Superman's origin has been retold a number of times with slight changes each time (often showing Superman doing things he hadn't originally done), but usually with the Cyborg himself narrating.
Since Cyborg Superman is obviously insane and hates Superman, some things are clearly false, but with other changes, like the cause of the radiation storm and what happened with Terri, it's hard to tell if these re-tellings are just the result of a crazy man telling his story or official retcons. For that reason, any changes in the origin are in the following paragraph.
When the Cyborg met Mongul, it is revealed that for some reason Henshaw believes that Superman was responsible for his loss of humanity and that he had banished Hank from
Earth. When the Cyborg battled Blue Superman at the Source Wall, he explained that Superman had caused the deaths of his friends because he was jealous and afraid of their abilities. While attacking Earth as a part of the Sinestro Corps , the Cyborg said that Superman had indirectly caused the radiation storm when he threw Eradicator into the sun.
He also said that Terri had been near death when he went to see her as a machine and that he was trying to save her life but she jumped out of a window when she saw him and, as a result, Superman tried to kill him.
Reign of the Supermen
After wandering the Universe and eventually losing his sanity, Cyborg Superman would ultimately return to earth and after spending several weeks convincing the world of his legitimacy as the “real” Superman by saving the president from terrorists and throwing Doomsday into space (secretly implanting a device in him that would allow Hank to always know his location in the process).
After an Alien spacecraft (Commanded by the original Mongul who worked for Cyborg Superman and worshiped the very ground he walked upon) suddenly appeared over Coast City and was approached by the Eradicator to discover it’s intent, Hank would then commit an act that would have severe consequences on the DCU for decades afterward (such as Zero-Hour and it‘s consequences).
This act had been fueled by many psychotic motivations like his desire to remake Coast City into his image, to forever discredit Superman, and to erase the memory of his wife Terri who was from Coast City, Hank destroyed the Eradicator, Coast City, and all of it’s seven million inhabitants.
He would later attempt to do the same thing to Metropolis but a squad consisting of Superboy, Supergirl, Steel, a rebuilt Eradicator, and a reborn Superman would eventually arrive to stop him.
The battle would reach it’s climax as Hank, Superman, and the Eradicator fought in the reactor of the Hank’s remade Coast City or “Engine City”, the kryptonite radiation in the room where they fought was so fierce it was capable of killing non-Kryptonians, Hank would destroy the Eradicator once more.
But as his blast went through the him the Eradicator changed the radiation into yellow sunlight and directed it towards Superman giving him the power to at last defeat Henshaw and obliterate him.
Hank would later send his consciousness to the device he had placed on Doomsday long ago and after Doomsday at last landed on Apokolips Hank would remake himself using Apkoliptian technology, effortlessly assimilating the New God technology into his being.
With Doomsday at his side he layed waste to Apokolips’s defenses even using Doomsday to defeat Darkseid himself, but his plans of conquest were foiled by Superman who delayed Hank’s triumph long enough for Darkseid to recover and defeat him with the Omega Effect. Darkseid would ultimately undo Hank’s imprisonment within the effect after being angered by Superman and sent Hank to plague him once more.
Hank would later hunt down Superman at the behest of an intergalactic tribunal who mistakenly believed Superman guilty of destroying his home planet of Krypton.
After capturing Superman, Supergirl, Steel, Superboy and the Eradicator he would later be captured by alien tribunal himself after they learned of his many crimes and of Superman’s innocence, they ultimately decided to cast him into a black hole and after eventually escaping that he was attacked by Hal Jordan as Parallax.
Their battle would take them to the brink of the Source Wall, a wall made of fallen gods, containing unfathomable power, and serving as the barrier between the various 52 universes and the Bleed (the highly radioactive space between universes). Parallax would ultimately destroy the Cyborg’s body and disperse his consciousness into the wall.
Henshaw would survive however by commandeering a piece of the source wall itself and after a brief confrontation with Superman Blue he would eventually travel beyond the Wall and into The Bleed (eventually learning of 51 parallel universes that existed beyond his own) before eventually somehow making contact with the Manhunters and becoming their Grandmaster.
As a result of the cosmic radiation, Hank Henshaw underwent a rapid degeneration but at the moment of his death, his consciousness jumped into a nearby computer.
From that point on, his consciousness became tied to machines. He can posses machines and anything even remotely electronically mechanical and is able to control them completely with an ability he calls "technomorphing".
Unlike most technopaths, he doesn't just command them, he incorporates them into himself and any nearby technology becomes an extension of himself. He can take any machine and, once it's a part of him, he can transform it into anything his mind can imagine, and thanks to his time spent traveling across the universe, he can imagine a lot.
And, even before becoming a living energy signal, Hank Henshaw was a genius, so this only adds to what he can come up with. The Cyborg is not limited by the uses or parts in the original machine, which makes this ability all the more dangerous. Due to the fact that parts of the Cyborg are cloned from Superman's DNA, he has many of the Man of Steel's powers.
He has exhibited heat vision (and other kinds of vision), super strength, super speed, invulnerability, and flight. It is assumed that if he created biological lungs for himself he could duplicate Superman's freeze breath, but he has not done so at this time. As with machines though, Cyborg Superman can modify his Superman parts beyond their original limits and weaknesses.
He has already removed his Kryptonite weakness and his understanding of biology seems so complete that he can create more living Kryptonian parts from machinery. Cyborg Superman is also immortal, being able to live no matter what happens to his physical body.
Currently, Cyborg Superman possess several Green Lantern Rings and ten Qwardian, Sinestro Corps Power Rings. These weapons are not just for show either. He never used them much and usually relied on his Kryptonian powers, however when he did use them he appeared to be rather adept.
Other weapons at his disposal include Willhunters, nanites which he uses to enslave a person's mind and make them loyal to the Manhunters, as well as hundreds of Manhunter robots which he has upgraded and started mass producing and obey his every command.
Recently, he took control of The Alpha Lanterns just as he once did with The Manhunters and has been reproducing Alpha Lantern batteries in order to turn Lanterns that have been kidnapped by his new soldiers into Alpha Lanterns themselves.