 Development of Dota 2 began in 2009 when IceFrog , lead designer of the original Defense of the Ancients mod , was hired by Valve for the same role . Dota 2 initially used the original Source game engine until it was ported over to Source 2 in September 2015 , making it the first game to use it . The game also allows for the community to create custom game modes , maps , and cosmetics for the heroes , which are then uploaded to the Steam Workshop . The popularity of Dota 2 has led to official merchandise being produced for it , including apparel , accessories , toys , and promotional tie @-@ ins to other games and media . 
