There is already an equivalent of "Path of War" for a hero from the "Sylvan" faction.
Added 22 minutes later
The simplest thing is to transfer the spell to attack. But that's not very elegant.

I just suggested it; I installed this mod to test it, but I didn't really want to use it; I don't remember why. I think it causes some problems with saves, or the game just doesn't play right; I can't remember:D

Added 3 minutes later
Well, I'll try to come up with something else interesting. For example: Cold Desert Wind - The hero starts with "Cold Steel," and for each level, the damage from this skill increases by 1%.
Or you can make the percentage higher, but add a permanent -1 morale to the hero.