Heroes 5.5 WarGame Edition - Tactical Edition.

As a backup solution, if it's technically impossible to implement something else, we could use the option of having tiers 1-3 for the "Vow" skill as the basic skill, and provide other types of bonuses for advanced and master levels, similar to the Orcs' "Distortion" skill (in this mod). For example, these could be standard bonuses like +0/+1/+2 to initiative or +0/+2/+4 to attack. I think we should implement this first, and then try other solutions. In that case, however, the "Vengeance Guild" would have to be replaced with a racial bonus of +10%. P.S. Even better, if different heroes have different tiers for the "Vow" skill, it would be difficult to counter all the Elves at once by refusing tiers 1-3.

Ultimately, if I know that the opponent will have a достаточно dangerous stack of high-tier units, then the motivation to find that specific stack on the map and put it on the "Vow" list is quite significant.

This approach doesn't work for me because there will be many armies, and focusing on just one is less effective. Imagine: the opponent has 2-3 producing cities of different races, you specialize the "Venger" hero against cavalry, and another army of wyverns kills you.