Yea, I know. Hollywood has run the X-Men franchise into the ground, but I still wouldn’t mind a Psylocke off shoot. Maybe revitalize the movies with a femme fatale angle. The storyline I think they should focus on is “The Transfer”. Here’s the science (It will make more sense if you have reasonable X-Men comic knowledge, but it’s still a good story):
Psylocke (Elizabeth “Betsy” Braddock) is a master of many forms of karate and is also a master of Ninjitsu. She wields a katana as her weapon of choice. She also has vast mental power: she can read minds, project thoughts and illusions, and she can manifest her powers more powerfully by attacking her victims with her psychic knife. Here is how a British psychic became fused with the body of a ninja…
To prevent the X-Men’s death, which she had foreseen in a precognitive vision, Betsy sent the team through the Siege Perilous, a device given to her by Roma, Merlyn’s daughter. The Siege Perilous would give them all new lives. Betsy awoke on an island near China without her memories. She was found by the evil ninja group, The Hand. The leader of The Hand, Matsuo Tsurayaba, wanted to save the life of his brain-dead girlfriend, Kwannon. To do so, he had Spiral’s Bodyshoppe switch Betsy’s and Kwannon’s souls. Spiral not only switched their bodies but also fused their minds and physical features. They shared the same memories and shared half of Psylocke’s telepathic powers.
Betsy was given to The Mandarin to serve as his assassin. While working as an assassin, Betsy changed her armour to a more revealing outfit, and learned to focus her psychic energy and turn them into the “psychic knife”. On her first assignment as Lady Mandarin, she had to battle Wolverine. When she stabbed Wolverine in the head with her psychic knife, it showed her his memories and revealed to Psylocke who she truly was. Psylocke then rejected her role as Lady Mandarin and escaped with Wolverine and Jubilee to Genosha. In Genosha Psylocke, Wolverine, and Jubilee discovered that the X-Men and the New Mutants had been captured by Cameron Hodge. They also met Havok on Genosha, then they went on and defeated Cameron Hodge. Once the X-Men were free they all headed back to New York.
When the X-Men split into two teams, Psylocke joined Cyclops’ team. She eventually started flirting with him and when Jean Grey found out, the two started fighting. They were interrupted when Kwannon (now calling herself Revanche turned up at the Xavier Institute (in Betsy’s body) and claimed to be the real Psylocke. Not knowing what or who to believe, the X-Men had no choice but allow her to stay. Revanche then confessed to Psylocke that she had contracted the Legacy Virus thanks to Spiral.Soon after, Revanche was mercy-killed by Matsuo Tsurayaba. Upon her death Betsy gained her full telepathic powers and the and remaining pieces of herself but was still able to retain Revanche’s martial arts skills. Kwannon’s fractured memories and personality were also removed from Psyocke’s mind by Matsuo who gained a small fraction of Kwannon’s psychic powers. Afterwards, Jean re-trained Betsy to use her telepathy, she also started a relationship with Angel. -Source ComicVine