IceFrog didn't create Dota, he took over maintenance of it from a long line of other people at the time, including Guinsoo (who added Roshan and the recipe system) who worked at Riot (though Icefrog was definitely the best maintainer, Dota was already hugely popular before Icefrog had anything to do with it).
Dota itself wasn't even original, it was based on a StarCraft 1 custom map.
Dota itself wasn't even original, it was based on a StarCraft 1 custom map.