Elizabeth "Betsy" Braddock, better known as Psylocke, first appeared in Captain Britain #8 (December 1976), published by Marvel UK and created by Chris Claremont and Herb Trimpe. Introduced as the twin sister of Brian Braddock, the hero Captain Britain, she initially possessed precognitive abilities and worked as a charter pilot and fashion model before joining the British intelligence agency S.T.R.I.K.E. Her mutant telepathic powers later emerged fully, and after being captured by Mojo and Spiral—who replaced her eyes with cybernetic implants—she joined the X-Men in the United States, adopting the codename Psylocke and making her prominent American debut in titles such as Uncanny X-Men in the mid-1980s.

A transformative development occurred in Uncanny X-Men #255–258 (1989–1990), when Betsy, brainwashed by the Hand and presumed dead, underwent a forced body swap with the Japanese assassin Kwannon, orchestrated by Spiral. Her consciousness transferred into Kwannon's body, granting her enhanced physical abilities, expert ninja training, and the signature "psychic knife"—a focused manifestation of her telepathy. This Asian-featured incarnation became the iconic Psylocke, serving as a core X-Men member for decades, honing advanced telepathic and telekinetic powers, and participating in major storylines involving threats like the Shadow King and Apocalypse.

In more recent continuity, beginning with the 2018 Uncanny X-Men: Disassembled arc and extending into the Krakoa era titles such as Excalibur (2019 onward) and Fallen Angels, the long-standing body swap was resolved. Kwannon was resurrected in her original body and reclaimed the Psylocke mantle, while Betsy returned to her original Caucasian form and assumed the role of Captain Britain. This separation addressed identity complexities and cultural sensitivities, allowing Psylocke to continue as a distinct, formidable psychic assassin within mutant narratives, while Betsy's legacy endures through her multifaceted evolution from telepath to warrior.