Fun fact: Atari doesn't own the Master of Magic trademark in the United States.
It was abandoned by Microprose and registered by Nival. (I couldn't find any evidence of registration in European Union countries or as a Community Trade Mark.)
Anyone who follows Nival know if they're planning a remake, like with King's Bounty?
Nival's lawyers only own the US trademark rights for the name, Master of Magic. They don't own the US rights for the game Master of Magic, which are still owned by Atari. Microprose didn't "abandon" this. In the scramble to sell off the company's assets, they neglected this. It's simply Nival wanting to scavenge a small piece of somebody else's pie if anyone should try to redo the game using the MoM trademark. That's all.
You're probably aware that ironically Stardock was negotiating four years ago with Atari for the rights to remake MoM with release both in the US and overseas. That fell through because of Atari's stringent marketing and ownership requirements. Stardock wouldn't have been in negotiation with Atari if Nival had owned the rights to the game.