Above is what is thought to be the sole instance of Jack Kirby inking himself on a Marvel project. The inking on this action rich cover for Fantasy Masterpieces #4 is not identifiable as any other artist in the Bullpen and so most folks think this is the hand of the King himself. I've read one opinion that suggests it might've been Roz, Jack's lovely wife who inked this piece.
Whatever the case, it's yet another vibrant cover from the hand of Kirby. And while it's still uncertain in my foggy memory, this just might've been the the very first Marvel comic I ever got hold of as a nubbin.