There is a lot of idle speculation being made in this thread with people jumping to conclusions with no basis. Konrad gave us very vague statements about this development.

Those familiar with the Descent IP know that it suffers from a fragmented state, with different parts held by different parties, with much animosity present between some of said parties. To immediately jump on the anti-Interplay bandwagon with no basis feels to me like picking a scapegoat just because they're someone you don't like.

Looking at what was said, we have the following clue: 'changing hands' - something changed hands, what? Given the fact that Interplay just entered into a licensing agreement with Descendent Studios for the use of the name at the beginning of this year, I really don't see the upside for them in selling their portion of things. They stand to make money off of this long-dormant IP if Descent: Underground does well, since Interplay is basically an IP Farm these days, that kind of relationship is consistent with their company structure.

So, what else may have changed hands since Descent was put live on GOG on September 9, 2008? Let's look at the history of Descent. Descent was developed by a company named Parallax Software and published by Interplay. As is well established Interplay owns the naming rights, with Parallax having retained rights to the rest of the IP. In 1997 Parallax split into two companies, Volition, Inc. and Outrage Entertainment. In 2000, THQ purchased Volition, Inc. and two years later THQ also purchased Outrage Entertainment. This makes it quite likely that THQ, at this point, gained ownership of the other parts of the Descent IP, most likely wholly as part of Volition.

Fast forward a decade, Outrage has been shut down and merged into the rest of THQ, Volition is still operating as a subsidiary of THQ, then in 2012 THQ declared bankruptcy and went into liquidation. On January 22, 2013 Volition was sold to Deep Silver for 22.3 million. The only franchise known to have changed hands at this time was Saint's Row, but it is quite possible that a dormant franchise like Descent could have been included in that transaction as a non-entity. Alternately, it's quite possible the IP could have been sent somewhere else, the prime candidate being Nordic Games who acquired several Volition franchises.

Of course there's another possibility. It's possible that Mike Kulas and Matt Toschlog retained the rights to Descent on a personal level, if that's the case then it's equally possible that they entered into a private transaction and sold their interest in the IP. Generally I would consider this to be the least likely situation as the sale of their companies likely included all IP rights in the transaction.

Either way, the most likely answer is that Interplay was not responsible for this move. They've been in business and active in defending their IPs for the entirety of the time that Descent has been for sale on GOG.com, they cannot possibly have missed the fact that Descent has been on sale here for seven years (and the chance to collect royalties on the sale).

It seems far more likely that someone like Deep Silver or Nordic games has taken notice of the franchise due to the new game being developed by Descendent Studios (it front-paged on Steam a few times already) and have started to look into exercising their rights to the IP, if they can. As everybody knows, the first rule to claiming IP over something is that you need to defend your IP when and if it's being infringed upon. When it was just GOG.com reselling copies of the old games for short money, it probably wasn't worth getting out of bed to companies like Deep Silver or Nordic, but now that there's a possibility of millions of dollars worth of sales of the new game, they might be taking an interest.

As noted, the other thing Konrad stated was that there are 'in-flux legal agreements' which indicates that negotiations are likely ongoing. Once again, this seems to reinforce to me the idea that someone new is trying to enter the equation and get a piece of the pie mandating three way negotiations between GOG, Interplay, and that third party.