It's not only the issue of the Fallout MMO that's got Bethesda's feathers ruffled with Interplay. According to a story being reported over at Gamasutra, Bethesda is suing Interplay for allegedly being in breach of the agreements the two companies signed in April of '07.

Part of the aforementioned agreements stated that Interplay would be allowed to sell pre-existing Fallout games such as Fallout, Fallout 2 and Fallout Tactics, provided that they sent all marketing materials (packaging, advertising, etc) to Bethesda for pre-approval. These stipulations were put in place by Bethesda to avoid consumers being confused as to who is the developer of Fallout 3, which Bethesda claims is now occurring due to the fact that Interplay did not seek pre-approval for these materials. Due to these claims Bethesda is asking for injunctions against Interplay's sale, manufacture, and distribution of pre-existing Fallout games.

More relevant to the MMOG aspect of this story is the fact that Bethesda is also looking to terminate their trademark licensing agreement for the Fallout IP with Interplay. Following Bethesda's purchase of the Fallout IP from Interplay, the IP was licensed back to Interplay towards the development of a Fallout MMOG, however there were some stipulations. One such stipulation was that Interplay would be required to be in full-swing development by April 4th, 2009, which Bethesda contended earlier this year was not the case.

If a decision is made in Bethesda's favor, Interplay will no longer be allowed to develop a Fallout MMOG, and will be required to pay legal fees and damages to Bethesda.

Via Gamasutra.