From the 1930s to 1990s, Jack Kirby created gob-smacking art and unforgettable characters, but he was mainly a storyteller. “The Pact,” “Madbomb,” the Galactus trilogy, Captain America’s origin, Silver Star, OMAC, and even Thundarr the Barbarian are among the thousands of tales he spun solo or with collaborators. But the greatest Kirby story is the…