While a child, Briar Raleigh was a victim of one of the mutant terrorist Magneto's rampages in Seattle, costing her family and seriously damaging her leg. She went to months of physical therapy to walk again with a cybernetic brace. She tracked Magneto down years later. Locating him in Saranac Lake, New York, Briar told him she could supply information to him that would be more valuable than anything his local contacts could ever give him.

Briar said that she believed that they were meant to work together, so she showed Magnus all the data that she had collected, a list of the S.H.I.E.L.D. agents tasked to capture him, their names, personnel files, potential blind spots, and points of weakness. But the real enemies were groups like the Marauders who were to blame for one of the worst massacres of all. Intrigued, Magneto took Briar up on her proposition,^[2] and, at her suggestion, re-programmed the Marauders' behavioral conditioning to follow his orders rather than those of Mister Sinister after he'd killed one more cell of them.^[3]

Briar was later seen alongside Magneto when they attended a formal meeting with the Hellfire Club's New York branch. As the M-Pox became more dangerous towards mutants, Magneto began making numerous allies to further his plans. Striking a deal with Sebastian Shaw, allowed Briar to gain membership into their Inner Circle as the Black Bishop, while Erik became the White King.

With Briar's connections, she was able to obtain a vial of gray matter from Someday Enterprises. She gave the sample to Psylocke, who was the only one able to read it, as she was a telepath. Due to Briar's evidence, the X-Men and the Hellfire Club investigated the company further, but as soon as they arrived, they were attacked by the same mutants who had asked for protection from Someday Enterprises.^[1]

Briar continued assisting Magneto during his following missions. When he returned to his ruthless methodology to ensure mutantkind's survival, he established a new Brotherhood of Mutants, and Briar was one of its members.^[4]

Briar has had cybernetic implants of Shi'ar technology, the full extent of which are presently unknown; however, at the very least they protect her from telepathic attacks or intrusions,^[5] as well as shield her from other forms of mental influence, such as Daken's ability to manipulate pheromones.^[6]

• Magneto (Vol. 3) writer and Briar's co-creator Cullen Bunn originally planned her as a character who was monitoring and guiding Magneto, supporting him in his quest. He then scrapped that idea in favor of using her as a window into a sub-culture of people who were "fans" of world-threatening villains.^[7]