NHF – new heroes for Heroes V 3.1.

There is no core here, like in NCF. More precisely, there is, but it is symbolic and weighs almost nothing.
All heroes level up. There is probably not much point in having a limited number, if you don't want to play as them, just don't choose them at the start and don't buy them in taverns. Plus, the idea of the mod also includes multiplayer, and synchronization is necessary for this mode.
If you still want to disable some heroes, I think Dyrman will give a short instruction.