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.
In its filing, Blizzard said that the Dota name has been used by the Warcraft III community for more than seven years, and is therefore associated with Blizzard.
"Valve Corporation has never used the mark Dota in connection with any product or service that currently is available to the public," read the complaint. "By attempting to register the mark Dota, Valve seeks to appropriate the more than seven years of goodwill that Blizzard has developed in the mark Dota and in its Warcraft III computer game and take for itself a name that has come to signify the product of years of time and energy expended by Blizzard and by fans of Warcraft III."
The complaint went on to state that Valve has no right to the registration its seeks - and if it is issued to Valve - it would damage Blizzard and its fans who worked hard for years on. The company added that the trademark would confuse consumers and cause them to believe that Valve's product is somehow associated with Blizzard and Warcraft III.
Finally, Blizzard said in its filing that Valve has never "released, distributed, or sold any products using the mark Dota, or, for that matter, any of the Dota Marks."
The company concludes that, "if Valve is granted registration of the Dota mark, it would obtain a prima facie exclusive right to use of its mark that would cause damage and injury to Blizzard."
Both Valve and Blizzard are working on Defense of the Ancients products. League of Legends is also a Dota-style product, because it was created by core members of the Dota community development team.