More complex scripts can also be written to create completely new objects, or modify or enhance the rules of the game. The ERM gives the mapmaker the capability to change the function and appearance of any standard map object in the game, for example, a chest could be altered to give more gold/experience than usual. These fans then began creating their own improvements to the map editor, which gave more flexibility in map making, but it was only when members of the WoG team came up with Event Related Model (ERM) scripting that WoG slowly began taking shape. The creation of this add-on began on February 2001 because WoG's creators were disappointed with the map editor that shipped along with the original HoMM III.

Heroes of Might and Magic 3 In the Wake of Gods is a free fan-made expansion to Heroes of Might and Magic III: The Shadow of Death.