What do a college-age superhero and a disgraced pope trying to save a saint have in common? They’re both comic book concepts that emerged from the mind of Robert Kirkman.

Mr. Kirkman, who began by self-publishing his comics, is a star on the rise. His books are favorites of fans and critics alike. MTV has announced plans to adapt Invincible, his superhero series. And this week at Comic-Con International in San Diego, Image Comics will announce that Mr. Kirkman is becoming its newest partner. Under the company’s structure, partners profit mainly from their own work but also have a say in what will be published.

“This is kind of a big deal for me,” Mr. Kirkman, 29, said by phone from his base in Richmond, Ky. “Image Comics as a company was founded by comic book creators for comic book creators.”

In 1992, seven top-selling artists who had primarily been working for Marvel Comics decided to form their own company, Image. They had grown frustrated with having little editorial control and limited financial benefit from working on corporate-owned characters.