>Otherwise you'd only learn how much he can actually disclaim iff you get sued by DC and are able to bring the contract into the scope of discovery, which isn't exactly guaranteed.
Wouldn't the legal and financial burden be only on him?
He is by all account the copyright holder. He says you can do the f. you want with his work. You haven't signed any contract with DC.
You release some derived work commercially.
DC might sue him for granting rights to a third party that infringe n exclusivity clause.
But you aren't bound by any contract with DC, you aren't infringing anything if the sole copyright holder expressely gave you the permission.
DC's argument would be that the exclusivity clause bars Bill from declaring his work public domain, and thus the dedication is null and void.
The law does distinguish between a license and a public domain dedication. If Bill had instead put Fables under, say, CC-BY, that license absolutely would be invalid - you can't license rights you don't have, and the person with exclusive rights would be able to sue anyone who used the work under CC-BY[0]. But the public domain is not a licensing agreement, it's dissolving the foundation of that license agreement, and there's no precedent for what happens when there's exclusivity clauses in play.
Because there's no clear precedent[1], that means any lawsuit involving these rights would survive a motion to dismiss, meaning that the "fuck around and find out" liability falls on anyone actually trying to use Fables as a public domain work. This is to DC's favor: if they sued Bill directly, Bill would be able to point out the numerous contractual breaches DC executed, which would dissolve their agreement. But if they sue a rando, they might just settle to make the suit go away. Even if the rando was motivated to prove DC wrong, they don't have standing to legislate contractual breaches DC made to third parties, so DC would be able to legally assert rights they might not even have.
[0] While Creative Commons wasn't involved, the situation would otherwise be identical to the Harmony Gold/Mechwarrior lawsuit. BattleTech, a tabletop giant robot miniature game, licensed some mech designs from various Japanese cartoons. Those same cartoons were also licensed by Harmony Gold and Frankensteined together into a single cartoon called Robotech. BattleTech licensed out their miniature game to Activision to make a PC game called Mechwarrior. Harmony Gold sued because mechs from their cartoon were in their PC game, and the ultimate result was that because of the exclusivity clauses in play, BattleTech's license to Activision for those specific mech designs was null and void, so Activision was infringing Harmony Gold's rights.
Yes, this is one of those legendary lawsuits that you hear about from MechWarrior fans in the same way that rhythm game fans will never forget what Konami did to In The Groove.
[1] I fully expect an actual lawyer to reply with clear precedent in DC's favor. The best search engine is to reply with the wrong answer on Hacker News.
>>>> you aren't infringing anything if the sole copyright holder expressely gave you the permission.
It's clear he's transfered some rights to DC via an exclusive license. He may be the sole copyright owner, but he isn't the sole person with an ownership interest in Fables, and it's not clear that a third party with an ownership interest (DC comics) can't sue you.
Wouldn't the legal and financial burden be only on him?
He is by all account the copyright holder. He says you can do the f. you want with his work. You haven't signed any contract with DC.
You release some derived work commercially.
DC might sue him for granting rights to a third party that infringe n exclusivity clause.
But you aren't bound by any contract with DC, you aren't infringing anything if the sole copyright holder expressely gave you the permission.