Blizzard acquired DotA-Allstars, LLC from Riot Games and filed an opposition against Valve in November 2011, citing Blizzard's ownership of both the Warcraft III World Editor and DotA-Allstars, LLC as proper claims to the franchise.[52] The dispute was settled in May 2012, with Valve retaining commercial franchising rights to the Dota intellectual property, while allowing non-commercial use of the name by third-parties.

https://en.wikipedia.org/wiki/Dota_2#Development