Fontanelle was employed by the New Son to sift through the memories of people close to Gambit, mainly to determine his true role in the Mutant Massacre, and to manipulate him into pushing his powers to their limits. Fontanelle eventually found out that Gambit would meet her mother in the past. After finding this out, through subtle manipulations she helped Gambit against the New Son and was fired. After the New Son terminated Fontanelle's services, she began to aid Gambit in piecing together the mysteries of both the New Son and the woman known as the Black Womb, who was Fontanelle's mother.
As the daughter of Amanda Mueller that makes Fontanelle the great aunt of the Summers brothers; Cyclops, Havok, and Vulcan.
A mutant telepath of fair to high power, Fontanelle does her best work sifting through her subjects' dreams. Whether or not she is limited to that type of telepathic connection is still unclear.