In the reality presented in What If..? (2nd series) #43, Sunfire's cousin Mariko wed the X-Man Wolverine. Together, they waged a war against the Yakuza to completely free Clan Yashida of its criminal ties. They were joined by Mariko's half-brother The Silver Samurai and made great strides towards their goal. When Sunfire returned from a government mission and learned of his cousin's efforts, he pledged his allegiance to Clan Yashida. Their progress in redeeming Clan Yashida was soon impeded by American crime lord Wilson Fisk aka the Kingpin, who took an interest in seizing control of Clan Yashida and through it, the Yakuza. To settle the matter, Wolverine challenged him to single combat. Fisk agreed but insisted that Shiro leave the site of the battle. Though Logan defeated the Kingpin, the day ended in tragedy. The Silver Samurai was secretly allied with Fisk and killed Mariko at his command. Wolverine killed the Samurai in retaliation and the Kingpin fled, confident that the resulting chaos among the Yakuza caused by Mariko's death would enable him to seize control as he had intended. What he did not anticipate was the swift return of Sunfire, who torched his limousine as he drove away. Logan wanted nothing more to do with the Clan following Mariko's death and handed over the Honor Sword and control of Clan Yashida to Shiro.--
In the Age of Apocalypse, the world was a much darker and harsher place. Apocalypse enforced his view of survival of the fittest by culling the population in order to separate the weak from the strong. The island nation of Japan served as a test ground for these cullings. Apocalypse and his son, Nemesis, committed genocide there, leaving Sunfire as the sole survivor to witness what was done to his people. They even immersed him in a pool of his countrymen’s blood. Having lost everything he lived for, Shiro became more reckless and nihilistic, possessing a death wish that drove him through combat. As a result, he burned away his own flesh, and his fiery form was only held together by a special containment suit.
After the death of Apocalypse, Sunfire and the X-Men attempted to rebuild America, working as official super-heroes for the new President and the Department of Mutant Affairs. The coming of a Celestial Ship and a mysterious new Overlord changed all that, as mutantkind once again rose to crush humanity under their heels. The few surviving X-Men retreated to Atlantis under the command of Magneto and Jean Grey as they vainly fought to hold back global genocide. When the X-Men learned the Butcher Beast of Apocalypse had returned to his New York labs, they struck quickly to prevent him from capturing the Celestial Lifeseed he had hidden there. Shiro acted impulsively and destroyed the Lifeseed before learning what it was.
Unfortunately, the Lifeseed was being hunted by Earth-616’s X-Force, a key factor in preventing the Apocalypse Ascension on their world. Trading information, Sunfire’s X-Men and this X-Force planned to retrieve two more Lifeseeds from a fallen Celestial Gatherer, in the hopes of saving both their worlds. The mission was a disaster, as several friends fell in battle, the overlord was revealed as their long-missing comrade Weapon X, and only one Lifeseed was located. Jean Grey made a unilateral decision to send X-Force home with the seed, thinking her world was lost. After escaping from Weapon X, Jean, Sunfire and the surviving X-Men made their way to Earth-616, joining X-Force against their ascending comrade, Archangel. Archangel intended to use a Doom Fountain fueled by atomic flames to cleanse the Earth and then re-evolve it using the Lifeseed. Sunfire selflessly plunged into the Doom Fountain, absorbing the energies into himself to prevent the devastation of a world not his own. Shiro remained in the Fountain well past his absorption limits, and his body was consumed by the atomic fires. He died, but the Fountain’s release was delayed long enough to save X-Force’s world.
The Sunfire of the alternate Earth X future timeline had eventually changed his views, and was a reasonable man who also happened to lead Japan’s own hero team, Xen. Shiro died a heroic death way before his time, but he left behind a son who not only inherited his mutant power, but also his leadership position. Lord Sunfire, as Shiro’s son called himself, however had troubles to keep Xen’s various members in line, most of whom were far older and more experienced than he. The final mission before the team fell apart involved Xen going to Asgard to rescue Dr. Strange’s love, Clea, from Loki’s clutches. Dr. Strange helped to convince the rest of Xen of the importance of this mission by summoning the dead Sunfire's spirit, and letting him briefly use his own body.----
In the Mutant X timeline, heroes and villains put their differences temporarily aside when anti-mutant hysteria rose on a global scale. Havok and the Six met with leading members of the Hellfire Club’s Inner Circle and the Japanese Sunfire, who informed the others that his government was already building concentration camps for mutants. However, halfway during the meeting, Sunfire suddenly attacked the others, although not without regrets. Obviously he had been forced by an unknown higher power into betraying his allies. When he was defeated, Sunfire felt he had disgraced his family and committed suicide.
In yet another reality, it was not Shiro, but his cousin, Mariko, who had the power of nuclear flame and chose the codename Sunfire. But the differences didn’t stop there - this version of Mariko was gay, and a long-serving member of her reality’s X-Men. It’s not even known whether there was a Shiro Yoshida in this reality. At one point, the female Sunfire became unhinged from time and had to join the reality-hopping team known as Exiles. Mariko found a temporary happiness with some other world’s version of Mary Jane Watson, aka Spiderwoman, but shortly afterwards she died during one of the team’s missions.
In the Ultimate Universe, Sunfire was a member of Alpha Flight and served the Canadian government. The entire team utilized the mutant-enhancing drug Banshee to enhance their abilities. Sunfire and her teammates used their boosted power levels to defeat the X-Men in order to kidnap Northstar. The X-Men, especially Colossus, did not take kindly to Alpha Flight’s abduction of Northstar and several team members took Banshee in order to be a match for Canada’s super-team and rescue Piotr's boyfriend. Little was revealed about this version of Sunfire. Unlike his 616 counterpart, he appeared to be perpetually aflame.
In the future reality depicted in Weapon X: Days of Future Now, Sunfire found his powers wildly out of control. He tried to use them to destroy Weapon X's Hawaii-based Sentinel factory but ended up severely injured with burns covering most of his body. He remained there and recuperated prepared to make the short journey to his native Japan should Weapon X choose to launch an attack from their island HQ. He was approached by Wolverine who was reforming the X-Men after most of the team was killed during an attack by Weapon X's forces. Sunfire refused at first, but eventually changed his mind. He joined Deadpool, Mystique, Aurora, Juggernaut, Wolverine, Archangel and Agent Zero as part of this X-Men revival. The team didn't last long as Agent Zero was still under Weapon X's control and killed most of his teammates, including Sunfire.
When the Scarlet Witch warped reality to create the House of M, her father Magneto finally achieved his dream of mutant supremacy. With mutants in control of the world, Japan was ruled by Emperor Sunfire. Under SHIELD advisement, Shiro initiated experiments designed to enhance and mutate normal humans. The results were horrific and violated numerous human rights. The Japanese government's secret project was discovered by a group of students at the New Mutant Leadership Institute and junior cadets at SHIELD. Among them was Surge aka Noriko Ashida, whose father had been Emperor Sunfire's chief human advisor. Years earlier, Shiro had taken Noriko into his care and treated her as his own daughter when he felt that her father was not nurturing her mutant gifts and ensuring her place in the new world order. Appalled by the atrocities they discovered, Noriko and her comrades defied Sunfire and threatened to expose his vile experimentations to the world. They faced certain death for their efforts but were spared when reality was suddenly