Dota 2
Dota 2 is a video game that was released in 2013. It is a sequel to Defense of the Ancients. Dota was originally a player-made map (also know as a mod) in Warcraft: Frozen Throne that proved to be successful with over 5 million active players. When Warcraft: Frozen Throne game got old, it was hard to continue game development. As a result, Valve Corporation, with the help of the original maker (Icefrog) started to develop Dota 2. We do not know the real name of Icefrog (which is an alias). Blizzard sued Valve over the copyright of Dota and lost.