NHF – new heroes for Heroes V 3.1.

Dyrman says that Tyris is associated with Iris, so there's no question about keeping that name, but I don't understand why Oyrkhin isn't appealing.

Funny, in my scenario, the shaman is named Taris.)
It's not possible to make this special ability involve setting things on fire; it requires a combat script. Unless you set things on fire right before the battle, but then there's already a similar special ability for some necromancer.
In general, everything depends on whether it's possible to give the orc a decent spellbook or not. If it is, then that alone would be a good special ability.)