Dave Cockrum, an illustrator who in the mid-1970s helped invent a dynamic new look and intriguing new characters for the moribund “X-Men” comics, paving the way for what became America’s most popular comic books and a billion-dollar movie empire, died on Nov. 26 at his home in Belpon, S.C. He was 63.

The cause was complications of diabetes, Andrea Kline, his former wife, said.

The X-Men are mutants who as a result of a sudden leap in evolution are born with latent superhuman abilities that usually manifest themselves at puberty. Stan Lee and Jack Kirby, two creative legends at Marvel Comics, created the odd group in 1963, but by 1970, fan interest, never great, had petered out. Marvel put new X-Men adventures on hiatus.

Enter Mr. Cockrum, who with the writer Len Wein, under the direction of the editor Roy Thomas, was assigned to restart the series in 1975. After an issue and a half, Chris Claremont replaced Mr. Wein.

New international characters with strange new powers sprang to life. They included Thunderbird, Colossus, Nightcrawler and Storm, and they joined compelling standbys like Wolverine to eventually be the heroes of a dozen comic book titles, cartoons and video games, as well as three movies that have together brought in more than $1 billion in worldwide box office receipts.