Two men have worn the Sunturion armor: Arthur Dearborn (Sunturion I) and Mike Stone (Sunturion II). A woman, Sandy Vincent, wore a similar suit and called herself Stratosfire. All three suits have been associated with the Roxxon energy company.
Major Story Arcs
Arthur Dearborn is a scientist who develops a cutting edge satellite to collect solar energy to help the Earth's energy needs. However, he can't get it financed. Eventually, he is able to convince Roxxon to build it, but they only agree to do it if he agrees to be converted to a being of pure microwave energy, so he can work on the satellite without constant supplies of food and water. He agrees, and works there until Iron Man arrives to check it out, due to an incident on Earth. The satellite, Star Well I, had accidentally shot a beam of energy towards the planet, and killed 200 Iowans. At first Iron Man is impressed with Dearborn's scientific goals, but when it becomes clear that Dearborn is unapologetic about the accidental deaths he had caused, they fight. Their battle causes a giant chunk of Star Well to fall towards Sarasota, Florida. They both individually try to stop it, to no avail. Then Sunturion channels all of his energy into Iron Man's armor so that Iron Man can create an enormous blast that deflects the satellite. This heroic act dissipates Sunturion's corporeal form, and that seems to be the end of him. However, his energy is merely dispersed. Roxxon builds a second suit of armor in an attempt to reintegrate him, but loses the armor at sea. This armor is later found by Mike Stone, who temporarily uses it to become Sunturion II (see below).
The Stratosfire Incident
After that, Roxxon makes a third suit, which it gives to another employee, who took on the name Stratosfire. However, Stratosfire becomes increasingly unbalanced due to the suit's energy transformation, and when she finds out that Roxxon killed her best friend, she becomes a loose cannon. Roxxon then "resurrects" Dearborn with yet another suit, and sets him against Stratosfire. Iron Man teams up with him. The first time they fight Stratosfire, Dearborn partially absorbs her energy and forces her to fly away. During their second fight, he manages to activate an internal self-destruct mechanism in her suit, killing her. The resulting explosion also takes away his own powers.
During the Stratosfire incident, Dearborn reveals that he knows Iron Man's secret identity, but pledges to keep it confidential.
The Vibranium Vendetta
During the Spider-Man Vibranium Vendetta storyline, Dearborn is still working for Roxxon, helping them create an artificial form of Vibranium called Nuform. Spider-Man, Iron Man, and Black Panther think Roxxon is up to no good and investigate. The Ghost also shows up to sabotage Roxxon, and they all battle. Dearborn comes in and is accidentally hit by a microwave blaster developed for the Nuform process. This blast turns him back into Sunturion, but also affects his sanity. Spider-Man hits him with more microwave radiation. He turns back to Dearborn and regains his self-control. He can now once again turn into Sunturion at will.
A company man to the bottom of his heart, Dearborn doesn't believe the heroes' assertions about Roxxon, and kicks them out. However, he investigates on his own, and becomes suspicious. Once again, Roxxon's Nuform warehouse is attacked by the Ghost, but now Ultron shows up with an army of androids as well! Dearborn tries to evacuate with the Nuform data in a helicopter, but Iron Man attempts to force the chopper down. Dearborn has the helicopter attack, and then turns into Sunturion to fight Iron Man himself. Finally they stop fighting, and Iron Man leaves. (The Ghost and Ultron both have their own trouble and leave as well.)
Ultron and his androids attack again later, and this time Sunturion teams up with the heroes. Sunturion fights Ultron alone, but Ultron figures out a way to twist Sunturion's ability to lock onto an opponent's energy beam and uses it against Sunturion, temporarily defeating him. They battle again later, and this time Sunturion temporarily takes down Ultron using his full-body energy blaze.
The heroes find out that the Nuform is unstable and turns into Antarctic Vibranium, which will melt all the metal in the vicinity. Iron Man asks Sunturion to teleport it all into the center of the Earth, but Dearborn pathetically feels like he couldn't do it without permission from his company superiors, even though it is an emergency. Iron Man ultimately deals with the Vibranium. Jonas Hale, the Roxxon vice president, tells Dearborn that the whole mess was caused by a few bad elements in the company, and that it has all been taken care of--whereas Hale actually masterminded the whole thing. Dearborn happily swallows the lie.
Several years later, Roxxon officials tell Dearborn that his energy form is dissipating--he will eventually completely disincorporate, and there is nothing they can do. However, he realizes that Roxxon really just doesn't want to bother paying to fix him when they can give his powers to some new employees instead. He goes on a rampage and starts destroying Roxxon properties, feeling betrayed by the company that he gave his life to.
Iron Man, Vision, and Carol Danvers arrive to stop him. Vision manages to actually hit him due to his similar intangibility powers, but Sunturion leaves. Roxxon officials fill the Avengers in on what's happening, and ask them to help. The Vision, who is feeling empathetic to Dearborn since he recently came back from the dead, tracks Sunturion down to his ex-wife's house. Sunturion tells him he now sympathizes with Stratosfire and wishes he hadn't killed her. Vision convinces him to come back to Avengers' headquarters. Stark and Henry Pym try to help him, but don't have enough information. Sunturion leaves in a rage once more and leads them to another Roxxon lab, where he shows them the other employees that Roxxon wants to turn into new Sunturions. The Avengers once again try to stop him but only Vision is able to affect him. Vision uses his solar crystal to absorb the mentally-unstable Sunturion's energy into his own body. He then uses that energy to destroy the Roxxon lab so they can't create any new Sunturions. Having been projected out, Dearborn once again takes his corporeal form. However, now that their lab has been destroyed, Roxxon suddenly offers to fix Dearborn after all, since that is now the cheapest alternative. Dearborn accepts, feeling that he has no alternative.
Major Story Arcs
A Battle with Daredevil
Mike Stone is a trucker who does a regular New York to Florida run for the mob. However, he is skimming off the top, and they fire him. While in Florida, he goes fishing, and accidentally catches the Sunturion armor that Roxxon had originally intended to use to reintegrate Dearborn.
He uses the suit to get revenge against his former employers. He kills a number of their goons and steals their dope, then works his way up to his former boss, Richard Knox. However, Daredevil gets there first and fights Sunturion. Sunturion is far too powerful for Daredevil and defeats him. However, Daredevil realizes that Sunturion has no heartbeat, and figures out that he must be pure energy. Daredevil rips off Sunturion's mask and Stone's energy dissipates into the air, leaving an empty suit behind. He has never been reintegrated.
Powers and Abilities
Arthur Dearborn is a highly proficient scientist and engineer, capable of designing an entire giant solar-radiation-collecting satellite that was cloaked to all technological scanning, including Iron Man's. Even Tony Stark was impressed with his technology when he visited Star Well.
Both Sunturions had similar powers, which derived from their armor, which turned them both into living energy. Their powers are also similar to those of Stratosfire. Some of the differences between the two Sunturion's powers may just be the result of Stone's lack of experience with his suit.
They no longer need sleep, food, or oxygen to survive, and could survive in space.
Sunturion I and II could appear in their armored forms or in their original human form, although in fact both forms were actually just hard energy: both the armor and the human forms were essentially a physical illusion. Sunturion I was also able to make other illusions out of light energy.
They could both fly; Sunturion I was able to fly markedly faster than Iron Man's experimental space suit and his Silver Centurion suit.
They could both teleport instantly and easily, including in battle situations. They could teleport long and short distances. Sunturion I was also able to teleport others, as he did when he teleported Carol Danvers from Earth into space.
Both Sunturions were superhumanly strong. Sunturion I was able to grapple with Iron Man. Sunturion II was able to rip the roof off a bus and throw it, and said he could juggle railroad cars. They were both able to easily withstand or absorb physical attacks like punches or a hail of bullets.
Both Sunturions could project powerful blasts of radiation from their hands. Sunturion I was also able to project energy in a unidirectional sphere around him, which he could use destructively, or to blind opponents.
Sunturion I was also able to absorb energy, and was powerful enough to drain part of Stratosfire's power. He was largely immune to energy attacks. If attacked by an energy weapon, he could absorb their power, then lock on to their energy stream and channel his own power back up through theirs.
Sunturion I could transmute matter into energy, and absorb that energy for his own use.
Sunturion I could also use energy to control and "read" computers, even very secret and confidential ones. He was able to control Stratosfire's internal self-destruct mechanism against her will, and was able to read telecommunications information from nearby satellite transmissions.
Sunturion II was able to tune into any sounds on earth, electronic or not, including human voices.
Sunturion I was able to create energy shields, which were apparently more powerful than Iron Man's Silver Centurion's own defensive capabilities.
Sunturion I was able to turn into an intangible energy form in addition to his solid energy form.