As a fan of Marvel comics for more than 35 years, I've been thrilled ever since the company emerged from bankruptcy. Despite occasional flops, Marvel's existence as a business has seemed fairly secure. Following the success of X-Men: The Last Stand, fans and stockholders can look forward to theatrical releases of Ghost Rider in February 2007 and Spider-Man 3 in May 2007. On the small screen, the live-action Blade series debuted Wednesday on Spike TV.

As Fool Tim Beyers reported, Marvel Entertainment (NYSE:MVL) announced a May 2008 release date last week for the big-screen version of Iron Man, a popular character introduced in the 1960s. As the first theatrical release to be produced by Marvel Studios, it will be the first from which Marvel will reap the lion's share of profits -- and assume significant financial risk.

Marvel's studio venture is a major departure from the low-risk licensing business model that attracted many of us Fools in the first place. And if that weren't enough to make a stockholder uneasy, on May 31 Marvel lost a major personal force behind its movie initiatives. Avi Arad announced his resignation as Chairman and CEO of Marvel Studios, Chief Creative Officer of Marvel, and a Marvel director. He will continue as a creative advisor for Marvel through 2006.

Arad takes with him the rights to produce subsequent entries in the Spider-Man movie franchise, as well as the upcoming Iron Man and Incredible Hulk pictures. Furthermore, as of the beginning of June, Arad owns around 5% of Marvel shares, including unexercised options. He has also stated several times that his shares are not frozen, and that he can sell them at any time. Arad will likely be working with Marvel for a while, but his fiduciary responsibilities will be to the newly formed Avi Arad Productions, not to Marvel or its stockholders.

So far, the only person leaving with Arad is his son, Ari, who earned producer credits on a number of Marvel films. Otherwise, Marvel's studio personnel remain largely intact. Still, Arad himself has been personally credited with putting together top-quality talent for Marvel's major productions. How strong will Marvel's Hollywood drive be without that deal-making engine?

Marvel watchers should keep a close eye on how projects develop, both with and without Avi Arad's involvement. For better or worse, Marvel is not quite the same company it was when revived nine years ago. And with its new financing stake, it's playing in a different league.

David Gardner found Marvel before it was well-followed on Wall Street, recommending it to Motley Fool Stock Advisor newsletter subscribers for a 472% gain. If you're interested in finding other great companies like Marvel, try Stock Advisor free for 30 days.

Fool contributor Michael Jaffe owns shares in Marvel. The Fool has a disclosure policy.