IceFrog is an anonymous DotA designer. He took authorship over the game after Neichus, the previous lead designer that took the duties of Guinsoo after he left DotA development to play World of Warcraft (some years later Guinsoo would have join Riot Games to develop League of Legends). Guinsoo's version of the game was entirely unrecognisable when compared to IceFrog's, due to the different aims that each author had for the game. Guinsoo had primarily focused on creating fun heroes, while IceFrog has committed a lot of time to balancing the game.
IceFrog was totally reclusive at the beginning of his career, refusing interviews and player interaction. However, he now talks to players through his blog, where he answers questions and announces releases.
IceFrog has been responsible for the entirety of the game's balance, through constant adjustment to heroes based on how they perform, remaking of heroes or skills which are difficult to stabilise, and the elimination of overpowering trends with sweeping changes. This constant and thorough routine has led DotA to become the competitive powerhouse it is today.
He is the current leader of the game, releasing new heroes and catering to the needs of his player base. He has spent the majority of 2011 developing Dota 2 with Valve, while updating the Warcraft 3 DotA. Once Dota 2 is officially released, he plans on continuing both games simultaneously.