Should Bethesda be successful in its efforts to block the release of Interplay's Fallout MMO, Interplay says it will terminate the sales contract which grants Bethesda the rights to create games based on the Fallout IP.

Bethesda purchased the rights to the Fallout franchise from Interplay in 2004 and licensed the online rights back to the publisher.

"We sold the Fallout IP to Bethesda in exchange for a certain amount of cash and the right to do the Fallout MMO," Interplay president Eric Caen told Eurogamer. "If they refuse to let us do the game, then the sale of the IP is terminated, and they will be allowed to do only one more Fallout, 5.

"But in that case, the IP will come back to us, and of course, we will complete our work and release Fallout MMO."

Fallout 5 refers to the next Fallout game from Bethesda, following Fallout 3 and New Vegas.

Caen explained that the original licensing deal provided Bethesda with the rights to produce three games and related DLC.

"They already did Fallout 3, then Fallout: New Vegas, and they can only do one more Fallout, 5, if the sale of the IP is cancelled by the court.

"We will love if we have to do Fallout 6 and sequels. But we will see what happens in court. It can be this year or later... We have the back-up of our shareholders to fund this fight."

As confident as Interplay sounds, it's hard to believe Bethesda would be fighting so strongly to prevent the release of the Fallout MMO if it believed there was any chance of losing the Fallout IP. Both Fallout 3 and New Vegas have been strong sellers for the publisher and it's no doubt already working on the next game.