Shiro Yashida was born the son of a woman exposed to toxic radiation at Hiroshima. While he was father as a UN Ambassador, young Shiro grew to hate the US for what they did to Hiroshima. Eventually, his mother died and young Shiro noticed that he had mutant powers. This led to Shiro’s first encounter with the X-Men, as the little nuclear reactor decided to blow apart Washington, D.C. for its crimes against humanity. His uncle Tomo pushes him to keep attacking the US, unfortunately Sunfire notices Tomo killing his father and that brings his first superhero outing to an end. The D.C. Police step back, as Sunfire murders Tomo in revenge and then we don’t see Sunfire for awhile until he fights Namor.
The fight against Namor leads to helping Iron Man defeat the robot Ultimo. Afterwards, Professor X comes calling to bring Sunfire onto the Krakoa rescue team. Sunfire agrees to one outing, but Xavier keeps pushing him to join the team. Sunfire helps and the team is freed from Krakoa, but Xavier keeps pushing the issue. Sunfire breaks all ties with the X-Men and flees to Japan. He temporarily reteams with the mutants to battle Moses Magnum, who is busy destroying Japan with terrible earthquakes. We later find out that Moses Magnum is able to do this after power amplification via Apocalypse. Sunfire would later encounter Apocalypse after he was kidnapped as part of The Twelve. That led to Apocalypse and Cyclops getting merged, then Sunfire disappared again until another writer decided to use him.
Sunfire keeps revisiting the team, as he seemed to have an Apocalypse shaped target on his back. While on a mission with Mystique and Rogue, Sunfire was attacked by Lady Deathstrike and had his legs severed. Rogue absorbed his powers to take the fight back to Lady Deathstrike, but the damage had been done. Many people offered prosthetics and other means to help out Shiro. But, it was the offer from Apocalypse to become a Horseman that gave the most promise. Unfortunately, this destroyed most of Sunfire’s body as he became a mirror image of his Age of Apocalypse counterpart. Shiro got his legs back, but he was almost always on fire and could never find relief.
Sunfire later joined the Marauders and took part in the attempt to capture the first new mutant birth since M-Day. Sunfire is eventually captured, but manages to slink away back to Japan. A year or so later, Wolverine finds him and offers him a shot at joining the Uncanny Avengers. Shiro agrees after hearing how the Red Skull desecrated Xavier’s body. Also, it seemed that Sunfire had gained a degree of control over the powers that Apocalypse amplified. While Shiro still had his fiery temper, he was able to turn off the full body glow. Sunfire fought bravely for a bit, but the storyline ended with the Celestials destroying the Earth. Now, Uncanny Avengers is currently rebuilding the reality that led to that happening.
Others have taken on the Sunfire name and related variations such as Sunfire’s sister pictured above. Leyu Yashida worked as part of Jean Grey’s emergency X-Men team right before the Morrison era began. There were also the popular alternate reality versions which may or may not get their own chapter. Ultimately, it’s hard to pin down what makes Sunfire work without tackling the dated late 1960s ignorance of Japanese culture. Also, it’s not like Sunfire was used in a ton of issues or books. He didn’t hit his 100th appearance in a comic until the 00s. Sunfire is also the cousin of The Silver Samurai and Mariko Yashida, comic fans tell you that when they can’t think of anything else to say about the character. And, with that…onto THUNDERBIRD!