Mariko Yashida, the alternate-reality version of Sunfire from Earth-2109, first appeared in Exiles #2 (September 2001), created by Judd Winick and Mike McKone. In this timeline, Mariko is a mutant with powers identical to the main universe's Shiro Yoshida (Sunfire), including solar plasma generation, flight, and heat manipulation. Raised in a strict traditional Japanese family, she rebelled after her powers manifested and her parents discovered her lesbian orientation, viewing both as curses. Fleeing to the United States at age sixteen, she joined Professor Xavier's X-Men, adopting the codename Sunfire and fighting publicly for mutant rights, which led to her disownment. A multiversal disruption threatened her reality by making her powers uncontrollably radioactive, prompting the Timebroker to recruit her into the Exiles to repair broken timelines.
Sunfire joined the team early, replacing the fallen Magnus, and proved a reliable, tactical member across numerous missions against threats like Galactus, vampiric Avengers, and alternate villains. She formed close bonds, including an unrequited crush from Morph and a profound romance with an alternate Mary Jane Watson (Spider-Woman) during a stranding on a Legacy Virus-ravaged Earth, which she described as the happiest time of her life. Notable events included surviving a vampire bite and contributing to cures in infected realities.
Tragically, Sunfire's story ended in Exiles #37 (January 2004), when a Brood-possessed Mimic collapsed a building during a battle; she sacrificed herself attempting to save civilians. Morph later buried her on Spider-Woman's Earth, deeming it more fitting than her disapproving family's world. As one of Marvel's early explicitly queer heroes, this version of Sunfire highlighted themes of identity, sacrifice, and redemption in the multiverse, with no significant appearances since her death.