NHF – new heroes for Heroes V 3.1.

Okay... But are you planning to develop NHF for single-player mode?

Single-player scenarios can contain many scripts that may conflict with the mod. But you can try playing it; there's just no guarantee.

In multiplayer, you can easily set up a computer opponent and play against the AI.
You can also enter multiplayer mode through single-player mode and try playing, but errors are possible; I test the mod in this way.