Leyu Yoshida and her brother Shiro were born to a mother who suffered radiation poisoning due to exposure to the atomic bombing of Hiroshima, Japan. As a result, she and her brother were born mutants, possessing identical powers. Her brother would go on to be the well-known Japanese superhero Sunfire.
Sunpyre was created by Scott Lobdell and Salvador Larroca and first appeared in The Uncanny X-Men #392.
As with almost every character that debuts in the X-Men the character has gone through somewhat of a metamorphosis from fresh rookie to skilled veteran.
Major Story Arcs
With the X-Men
Leyu first appeared, during the Eve of Destruction storyline, when she joined the X-Men for a single mission, to help fight Magneto. Jean Grey had summoned her brother, but instead got Sunpyre, as Shiro was unavailable at the time. Despite Jean not knowing Sunpyre at all, she easily accepts her offered assistance as the situation was so extreme. Jean's makeshift team of X-Men consists of long-term allies Northstar and Dazzler.
There were also civilians Omerta and Wraith. Dazzler had problems of her own and with a Jean-assisted telepathic conference, Sunpyre learns of the child-like Age of Apocalypse villains. Thus, Sunprye is one of the few in current continuity to have any idea the Age of Apocalypse actually had happened. Sunpyre fights valiantly against Magneto, but almost loses her life when the master of magnetism constructs a metallic cocoon around her. After the mission was completed successfully, Sunpyre chose to return to her home instead of stay in the United States with the "arrogant" X-Men.
X-Corps and Death
Banshee later requests her to join his X-Corps (again replacing Sunfire, who didn't want to join). This time she was removed from the front lines and instead spent most of her time in the laboratory studying the mutant Abyss. When Mystique, who had infiltrated the group and brought together the other former villains, began her plan for taking over the X-Corps, Sunpyre was one of the casualties. Mystique stabs her to death.
When Banshee finds her corpse, he is also stabbed but he survives his wounds. Mystique had wanted to release Abyss, but she got more than she bargained for when the mutant was unable to turn off his powers and sucked the shapeshifter into the dimensional void in his chest cavity.
Powers and Abilities
Sunpyre was a mutant with the ability to convert solar energy into intense heat or flame and could surround herself with a protective aura of flame.
Her powers also granted her flight that could propel herself through the air at superhuman speeds, heat vision, and immunity to radiation and heat.