Byth Rok was a self-styled Master Thief from the planet Thanagar. He acquired a 'changeling' pill that allowed him to change shape at will. He used his powers to commit crimes on Earth, but Hawkman and Hawkgirl were eventually able to capture him.
In prison, Byth learned how to make the changeling pill himself. He regained his powers and again committed clever thefts, only to be taken down again by Hawkman and Hawkgirl.
