The curiously-named Ernst, whose physical appearance suggests that she may be a teenage girl suffering from progeria, became a student at the Xavier Institute not long after the psionic entity called Cassandra Nova had disappeared there. While Nova's disappearance and Ernst's subsequent appearance may or may not be connected, no information on Ernst's life before becoming a student in Charles Xavier's so-called Special Class could be obtained, nor could the nature of her genetic mutation be identified. Ernst, who appears to have befriended her disembodied fellow student Martha Johansson, briefly joined the so-called Brotherhood assembled by the mutant Xorn when he went on a drug-induced, destructive rampage in New York. Ernst did not show any signs of aggression herself. Ernst is one of the 198 mutants who have retained their powers after the events of "M-Day".