Psylocke started off as a British blonde twin sister of Captain Britian. She dyed her hair lilac when she was a fashion model and retained it afterwards.
Back in the late 80s, during the Australian days, she went through the Siege Perilous and emerged several issues later as a Japanese woman, Lady Mandarin, an assassin for the Hand who happened to have dark purple hair.
Years later, a woman named Kwannon appeared in Psylocke's original body. It was revealed that Spiral had switched the bodies and in the process fused their minds and DNA so that were indistinguishable. Kwannon died of the Legacy virus in the 90s
Most recently a few years back in the Sisterhood story, Madelyne Pryor attempted to come back but being that she was a psychic ghost, she had no body, but her goal was to find and reanimate Jean Grey's corpse for herself. In order to test run this idea though she had Psylocke abducted and had Spiral switch her back into her original British body, which was restored. All I remember is that she stuck a psychic knife in her head and that caused her to switch back into the Asian body.
So there you have it, she's switched bodies 3 times, its confusing and doesn't make a awhole lot of sense. And this doesn't even account for how many times her powerset has changed over the years...
