Kimberly Potters was a mutant in the year 2099, when an invitation to Xi’an’s gathering gave her the opportunity to join his newest incarnation of the X-Men. While at the gathering, Serpentina, nicknamed Tina, met with a scared and confused Timothy Fitzgerald. She greeted him and tried to put him at ease, showing him her powers, and introducing him to the entertainment of the day, the mutant Metalhead. She told him that Xi’an had called them there and told him that he would change his life. But when an assassin fired at Xi’an, and Tim fired a bolt of siphoned energy back at him, ruining his aim, Tina fled along with the other X-Men from the Synge Corporation, who believed that Xi’an had killed their former head, Noah Synge.
While a group of the other X-Men broke into the Synge Corporation building to clear Xi’an’s name, Serpentina was left behind with Cerebra and Timothy when Junkpile attacked them and stole Xi’an’s body, which had cocooned itself to protect itself from injury. Tina jumped on Junkpile, but was thrown towards a chasm, only surviving by grabbing the ledge at the last moment.
When the first group was captured, Tina and the remaining X-Men made their way into the Synge Corporation building, themselves. They found Meanstreak and Metalhead floating in stasis gel, but Tina smashed open the containers rather than see her friends imprisoned, and freed them. Together they fought through the building’s security forces, towards the office of Lytton Synge, where they ran into Junkpile. Before the rest of the team could form a strategy, Tina leapt forward and attacked him, but he quickly reacted and crushed her face into a concrete wall, killing her. When Xi’an rose from his cocoon, he tried to heal Tina with his newly evolved powers, but he found that he could do nothing for the dead. And so the X-Men buried Tina in a crystal coffin created by her fellow member, Krystalin. Yet, because she believed so fiercely in Xi’an’s vision, her death galvanized Timothy into permanently joining the X-Men.
Later, in order to use her against the X-Men, the Graverobber revived Tina’s body and used her as a mindless puppet against Xi’an’s team. When one of the other members of the Undead team lured Timothy, now called Skullfire, into an alley, Tina shot and killed him with a poisoned dart so that Graverobber could revive him to use his powers. But when Morphine Somers tricked the Graverobber by planting a bomb on the hostage he demanded, and destroyed him, Tina was freed from his spell and fell dead once again. The X-Men then cremated her so that she could never be revived again and spread her ashes to the wind.