Kwannon is first seen as the prime assassin of the Japanese crime lord Nyoirin and lover of
Hand assassin
Matsu'o Tsurayaba. With the criminal interests of Nyoirin and the Hand quickly coming into conflict, Kwannon elicits a promise from Matsu'o that they will fight to the death rather than betray their respective lords. During a duel at the estate of Nyoirin, Kwannon eventually falls from a cliff; with her physical injuries and lack of oxygen while underwater causing her to become brain-damaged and comatose. Nyoirin, who possesses an unrequited love for Kwannon, bids that Matsu'o take her to the Hand to be healed, with the promise that he will not cross their organisation again. The Hand is able to use their scientific and mystical resources to keep Kwannon's body alive, but is unable to resuscitate her mind.
Betsy Braddock body swap 's body, as Revanche. Around this time, the Hand discovers
Betsy Braddock washed ashore on one of their bases in the
South China Sea, suffering complete amnesia after having passed through the
Siege Perilous. Meanwhile, Spiral meets with Nyoirin, heavily implying that Betsy's former body now contains the remnants of Kwannon's mind. Seizing this opportunity, Nyoirin takes this body back to his estate, nursing Kwannon back to physical health, while at the same time retraining her and feeding her lies regarding her history and identity. Confronted by
Charles Xavier and the
X-Men, Kwannon states that she is the real Betsy Braddock, and that the Psylocke they are harboring is an imposter sent by Nyoirin to assassinate them all. The Legacy Virus increases Revanche's powers, restoring her memories. Revanche then confronts Matsu'o, who denies any involvement with her and Betsy's situation. With her death imminent, Revanche begs Matsu'o to kill her, to which he complies. Her death is felt telepathically by Psylocke and
Archangel, while some of the telepathic energy she wielded is imprinted onto Matsu'o. Still trying to find her place in this new era, she becomes part of a loose group of mutants that include
Kid Cable and
X-23, as the
Fallen Angels. Soon after, she assumes a leadership role in another team of outcast mutants: the
Hellions, alongside
Havok, John Greycrow (formerly
Scalphunter),
Empath,
Wild Child, Mister Sinister, and
Nanny and Orphan-Maker. When Betsy arrives on Krakoa, she actively avoids Kwannon due to having taken over her body for many years and corrects several people who attempt to refer to her as Psylocke. During
Excalibur, Betsy is accidentally transported into the body of Queen Elizabeth III, an alternate reality version of herself. In this reality, Kwannon is the ex-wife of
Angel, the Queen's lover and she reluctantly helps Betsy find her way to
Otherworld so that she can return to her original universe. Betsy attempts to find out more about the life of this Kwannon but, after Kwannon reads her mind and finds out about their history, she becomes angry and sends Betsy away. When Betsy returns to her original reality, her teammates suspect that the woman presenting as Betsy is not the real one. As
Rogue and
Rictor search
Apocalypse's lab for answers, they are attacked by Betsy but are saved by Kwannon, who states that it is not the real Betsy Braddock. Kwannon joins a magic ritual that aims to reunite Betsy's consciousness with a clone body but, when this fails, she releases Betsy's consciousness, much to the anger of Excalibur. Kwannon states that only she will be able to find Betsy and heads into Otherworld, where she locates Betsy's consciousness attacking a village. The two battle psychically, with Betsy stating that she is in too much pain over her failures and over what she did to Kwannon that she feels as though she can't go on and demands Kwannon leave her spirit to rest, but Kwannon states that her spirit is hurting others and tells her that she is worthy to be Captain Britain. Kwannon explains that neither of them were at fault for Betsy taking over her body and that there was no way to "fix" what had happened, rather they both just have to accept that there will always be a connection between them. Kwannon then takes Betsy's soul back to their original reality and returns it to her body, bringing her back to life and finally ending their previous animosity. During the events of
Inferno, Psylocke replaces
Gorgon as one of the Great Captains of Krakoa. ==Powers and abilities==