McKinley Franklin editor Robert Kirkman, the creator of the “Invincible” comics and series, believes seven to eight seasons of the animated superhero show would be enough to cover the scope of its story. “I’m trying not to pin it down to a number, because it is somewhat of a moving target. I think in the seven-to-eight-season range seems like it would be enough,” Kirkman said in a recent interview with Polygon.