Luuke Skywalker (note the spelling of Luuke, not Luke) was a clone created by Joruus C'baoth. It was cloned from the hand Luke lost in the course of his battle against his father,Darth Vader, on Cloud City. The clone, as had been all the
clones that have been developed too speedily in their Force resilient vats, was mentally unstable and dangerous. Luuke, the clone, was defeated by Mara Jade (Mara was then Luke Skywalkers wife)
Mark Hamill played Luke Skywalker in the three Star Wars films, and also the voice in the Star Wars and The Empire Strikes Back Radio Dramas that played on National Public Radio.