NHF – new heroes for Heroes V 3.1.

I would like to see a Warlock with mirror magic (like the Djinn for Mages). But to make it original, you could add this feature:
An enemy spell that deals damage can be reflected with a certain probability to any of their units. At the same time, the element will change to the opposite.

For example, the enemy casts Ice Bolt. When it is reflected, it turns into a fireball and hits their units.