Sunfire (Joint Venture)

Sunfire is a mutant superhero and vetern of such teams as the X-Men and Big Hero 6. This is the Joint Venture Universe incarnation of the character.

Early life
Shiro was born into Clan Yashida, one of the oldest, most powerful, and most respected families in Japan. His family was a staunch believer in tradition, including the possession of a "Lady" or "Lord" of the family, to whom the rest of the family answered. His mother, tragically, perished in childbirth, so Shiro never knew her, but he and his sister were raised by the Clan, so he never truly felt the loss.

None of this mattered to Shiro or his twin sister Rei in the slightest. They spent their days at school and their afternoons engaged in separate pursuits; Shiro would study different martial styles, hoping to emulate his elder cousin Kenichiro, the clan's honorary protector, whom he quietly idolized.

Shingen, Saburo, and Tomo - Feuding Brothers
The head of their household, Shingen, was a corrupt and cruel man, with many in the family planning to overthrow him. Two such were his brothers: Tomo, and Shiro's father Saburo. Both men had very different reasons for wanting Shingen deposed: where Tomo was only interested in his own power, Saburo genuinely cared for the rest of his family, putting their needs above his own even in the face of hardship.

Sadly, Saburo's selflessness would be his downfall, as well as Shiro and Rei's. Tomo, looking to gain an ally in taking down Shingen, and a scapegoat of things went wrong, convinced Saburo to break into Shingen's office one night and steal documents exposing Shingen's corrupt dealings with crime organizations from around the world. When they were discovered, Tomo pinned all the blame on Saburo, and Saburo, bearing the brut of it, took himself, Shiro, and Rei, and went into voluntary exile from Clan Yashida.

Life Outside the Clan
Saburo moved with Shiro and Rei to the United States, where they faced their fair share of prejudice, but also earned great respect thanks to their intelligence and Shiro's martial arts prowess. He became a sort of unofficial sensei to the other students, teaching them the moves he knew, while Rei's beauty, intelligence, and approachability secured her popularity.

Saburo, unfortunately, was not so lucky. He had secured a job as a technician at a nuclear power plant near Silicon Valley, California, but within a few weeks of working there, the reactor overheated and threatened to destroy the plant and most of its surrounding environs, including a good chunk of the capital. Saburo, ever the selfless one, went in and stopped the chain reaction before it could start, but in the process was inundated by so much radiation that he became gravely ill. He managed to make it home, but did not last the night. Finally, as Shiro and Rei held his hands as he passed away, something unesxpected happened.

Sunfire, Sunpyre, and the Return to Japan
Perhaps it was the buildup of radiation in Saburo's body, or perhaps the emotional devastation of losing their father, but Shiro and Rei's mutant powers catalyzed the instant their father died. Now both commanded the raging fires of the Sun itself. After serious discussion, the siblings knew they had to return to Japan and avenge themselves on their uncles -- the one who had betrayed their father, and the one who had condemned him. Designing costumes for themselves (though Rei took a decidedly more Animesque approach to hers), the siblings flew back home under their own power, travelling across the Pacific Ocean in a matter of hours and hardly even winded when they arrived on the outskirts of Tokyo.

Unfortunately, somehow, Tomo was ready for them. In their absence, Tomo had grown suspicious and paranoid that Saburo would one day seek revenge. He hired the Hand, a league of mystical assassins operating throughout most of Asia, to protect him from any attackers. At the same time, an outsider, a Canadian named James Logan, had met Shingen's daughter Mariko on one of her diplomatic visits to the West, fallen in love, ansd subsequently, fallen headlong into the turmoil that was Yashida family intrigue.

Neither Shiro and Sunpyre, nor Logan were any match for the Hand individually, there were too many, and they were too well trained. It was only by working together, and with the assistance of a thrillseeking cat burglar named Yukio, that the mutants managed to overcome their opposition. Shiro killed Tomo himself, blasting the coward through the heart with a single bolt of his atomic fire.

The thrill of victory didn't last long for Shiro, however. He was shocked and angered to learn that Shingen had forced his cousin Mariko into marriage to Noburo Hideki, a selfish man whom she did not love, a cruel man who abused her, purely out of spite for the Westerner, Logan. Rei, who had always been close to her cousin, ended up killing Hideki for what she viewed as unforgivable treatment of Mariko, whom she had idolized as a child as much as Shiro had Kenichiro. Shiro wanted to kill Shingen himself for his disgraceful abuse of his family, but Logan had beaten him to it.

Troubled
After the death of Shingen, Lady Mariko became head of Clan Yashida, uniting the surviving family members in a way they had never been before...that is, until she announced to all of them that she was going to marry the man she loved, the Canadian Westerner Logan.

Shiro took this news the hardest. He had witnessed firsthand the cruel treatment Mariko had suffered at the hands of Hideki. He knew that Westerners like Logan often hated his people, and treated them with the same cruelty and unfairness. And he knew Logan -- an ugly, caustic, alcoholic roughneck, who could more often than not be found in bar brawls, alleyways, and gutters, who seemed to Shiro to be more animal than man. His objections were ignored, however, as Mariko simply stated that he would like Logan better once he got to know him. Rather than take that chance, Shiro stormed out, needing some air and some space to cool down. No one knows for sure if he would have come back after calming down, for that was the last time anyone in Clan Yashida saw him in Japan.

Abducted by Weapon X, rescued by the X-Men
Shiro was ambushed, and captured -- not by members of the Hand eager to avenge their fallen comrades or their deceased employers, but by Japanese agents of the international organization called Weapon X. They flew him to their headquarters in Alkali Lake, keeping him locked in a cryogenic freezing tube so that he had to focus all of his flames on keeping himself from freezing to death and could spare none to escape.

Weapon X was all set to experiment on Shiro -- but while the scientists bickered and vacillated on what kind of Weapon they could turn the young pyrokinetic into, Logan had enlisted the help of other mutants -- the X-Men -- to save him. Seeing a team comprised mainly of Westerners come to his aid -- with his hated nemesis Logan at the forefront, no less! -- made Sunfire reconsider his stance on the West. After speaking with the X-Men's founders, Professor Charles Xavier and Magneto, Sunfire decided to go back to America with the team as one of them, to learn what he could about the world outside his family's intrigues and his own preconceptions.

Powers
Sunfire is a mutant with the ability to absorb cosmic rays, sunlight, and other forms of radioactivity and convert them into thermokinetic energy for his own use.
 * Plasma Blasts: He has the ability to project the flames he generates as powerful blasts of energy.
 * Plasma Emanation: Sunfire can generate plasma temperatures of about 1,000,000 degrees Fahrenheit at maximum level. He can also release his power in a massive, omnidirectional "Supernova" that creates a sphere of superheated plasma around him. However, Shiro has near-absolute control over the area of effect, enough to where one person may feel like they have been sunbathing all day, while a target next to them could be totally incinerated.


 * Heat Signature Sense: Shiro has the ability to sense the presence of living beings by the heat signature they give off.
 * Plasma Shield: Sunfire can manipulate plasma around him to such a degree that he can form an aura of flame that can destroy incoming weapons, melt bullets, and severely injure most physical attackers.
 * Flight: Sunfire can use his powers to create super-heated air currents which push him forward through the air, enabling him to fly. This super-heated air is often visible as a trail of flame behind Sunfire. The upper limit to the speed Sunfire can achieve while in flight is not yet known. He can also carry someone else on these air currents without having them suffer any significant damage.
 * Pyrokinesis: In a more general sense, Shiro can control and manipulate any fire or flame he creates, and utilize them in any way imaginable. He can alter his flames' shape, size, intensity, density, temperature, and even color to virtually anything he wishes.
 * Welding and Fusing: A specific use of his pwoers Sunfire trains in: His fire can burn hot enough to melt nearly any metal, and he possesses enough fine control over his flame to weld and fuse metallic objects together.
 * Fire Immunity: Shiro is resistant to heat and flame up to the maximum temperature of fire he can generate.
 * Radiation absorption: Due to the nature of his power, Sunfire is effectively immune to harmful radiation. Any suffient quantity will simply be metabolized by his body into fuel for his flames.

Weaknesses
Volatile Temper:  Shiro is often reckless and impulsive, given to rash action and highly reactionary behavior. He is easier to anger than most of his teammates, and often reacts more violently as well.

Physical Limitations: Although he is immune to heat and fire, manipulating solar plasma does take its toll on Sunfire. When he is tired or injured, his ability to control his fire is limited, and he runs a greater risk of inadvertently burning things -- or people -- he does not wish to.

Radiation stores: Sunfire's power draws from an energy reserve of absorbed radiation. If he is cut off from any source of radiation for too long, Shiro will eventually run out of energy and be unable to produce a flame.

Weakness to Cold: Shiro's powers typically protect him from the cold automatically. However, concentrated blasts of intense cold will force him to turn his powers inward to compensate, which will use up his reserves faster. As such, he is vulnerable to cold attacks, like Iceman's ice powers or a concentrated, sustained blizzard from Storm.