Son of The Mist, Kyle was groomed to take over his father's role as The Mist, much as David Knight groomed himself to follow his father. Kyle was the obvious favorite of his father's children, but in an ususual turn in this situation, he drew no resentment from his sisterNash. The two were both very close, even for brother and sister.
It was Kyle who killed David Knight during The Mist's final crime spree. He also blew up Jack Knight's shop and tried to kill Jack himself in a duel in the sky. Jack won the duel however, and Kyle was cremated alive on Jack's Cosmic rod. It is Kyle's death that prompted Nash to later become the second Mist.