HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

Moving the autobattle feature to ImprovedGameplay means that it can only be used against an opponent with the same version of the mod. In other words, when playing against ideological opponents, or those who simply don't want to install/update the mod, you'll have to do without quick battles or accept that a quick battle, like an angel versus butterflies, consumes mana.