Warcraft developer Blizzard has filed an opposition over Valve's registration of the DOTA trademark back in August 2010. Yes, the two PC gaming titans are duking it out in a court of law.
According to the filing, Blizzard claims Valve has no rights to DOTA mark, pointing to "more than seven years of goodwill" that it has backed the DOTA name with.
Despite having no "official" ties to Warcraft itself, Blizzard asserts the trademark registration will not only damage them, but the "the legions of Blizzard fans that have worked for years