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

In HotA, we will implement gameplay elements tailored for the Overlord mode, which will allow players to engage with the Overlord mode for a longer duration – focusing not on a fixed game date, but on the state of the game. Intelligent algorithms for interrupting the Overlord mode, which will allow players to play the Overlord mode to the fullest extent, will be developed in collaboration with Sav or even by him alone (I'm not sure if I'll have time).
So, the most advanced and complete Overlord mode is only possible within HotA.