The heirs of late comic-book creator Jack ‘The King’ Kirby served 45 copyright-termination notices to Marvel Entertainment Inc., Walt Disney Co. and other Hollywood studios relating to comic-book characters and stories created by Mr. Kirby, including “X-Men” and “The Fantastic Four.”

Mr. Kirby’s four children are seeking to recapture as early as 2014 copyrights to characters he created. Those creations and co-creations are currently owned by Marvel. But if the heirs gain control of the copyrights, they could license them without Marvel’s permission, or at least secure a share of the profits generated by those characters.

The heirs served the notices under the auspices of the U.S. Copyright Act, which permits authors and their heirs to terminate old copyright grants after a long waiting period, allowing them to recapture the rights for their own use.

The children of Kirby, who died in 1994, are being represented by Los Angeles law firm Toberoff & Associates, which has represented Superman co-creator Jerry Siegel in a similar claim against Warner Bros.

Kirby, who is widely considered to be one of the most influential comic book artists of all time, served as penciler and a co-plotter with writer Stan Lee on most of the Marvel characters in question. If Marvel, Disney or any of the other companies challenge his claims, it may be a complex legal process to determine what exact role Kirby played as creator or co-creator of various characters who first appeared nearly 50 years ago.

While Stan Lee, who has also been Marvel’s editor in chief, has been a public face of the company for decades, Kirby is less well known publicly despite the fact that he worked closely with Lee on many of the publisher’s best-known characters. Which is partly because Kirby left to work for competitor DC Comics in 1970.

Under copyright law, creators and co-creators can seek to regain copyrights they previously assigned to a company 56 years after first publication and can give notice of their intentions to do so up to 10 years before that.

Kirby’s children would be eligible to claim their father’s share of the copyright of the Fantastic Four in 2017, while the Hulk would come up in 2018 and X-Men in 2019. The copyrights would then run for 39 more years before expiring, after which the characters would enter the public domain under current law.

A spokeswoman for Disney said:

“The notices involved are an attempt to terminate rights seven to 10 years from now and involve claims fully considered in the acquisition.”

As we told you last month, Disney agreed to acquire Marvel for $4 billion.

We’ve also told you about the federal court lawsuit involving the heirs of “Superman” co-creator Jerry Siegel, who recently recaptured limited rights relating to the original “Superman” from Time Warner Inc.’s Warner Bros. and DC Comics.

This story is still developing and we’ll bring you the latest…