Tatsu Braddock was a metamutant who left her quiet home in England to travel the world and eventually became the sword-wielding mercenary known as Kokoro (the Japanese word for “heart”). Joining the JLX, she was caught in a love triangle with fellow teammates Nightcreeper and Angelhawk. At some point, Kokoro found herself being hunted by Sinistron before being saved by the timely arrival of Magneto and The Magnetic Men.
Kokoro possesses telepathy and is a skilled ninja. She can also create blades of psychokinetic energy by combining her powers and ninjitsu training, allowing her to deliver a physical and mental blow.