Blizzard has challenged Valve's efforts to secure a U.S. trademark on Defense of the Ancients - something it said it had no plans of doing. In 2011 Valve announced plans to create a sequel to the popular Warcraft II mod, Defense of the Ancients. At the time Blizzard said that it would not oppose the company, but said that it was confused by the move. Today we learn that Blizzard filed a complaint with the U.S. trademark in opposition of Valve's registration of the Dota name in late 2011.
































