Heroes 5.5 WarGame Edition - Tactical Edition.

...and if you remove the ranger guild from the city, the reset will never happen.

Added 2 hours 28 minutes later
Okay, let's say we pre-define sworn enemies for each ranger (I still suggest three from each race, excluding neutrals and possibly units from the Forest Alliance itself), and this gives us "Avenger Novice," but then what will levels 2, 3, and 4 in the Avenger skill give?
Maybe we could do this:
Avenger 1: The list of sworn enemies includes three units from each race.
Avenger 2: The hero's direct attack is enhanced (deadly shot).
Avenger 3: The chance of dealing double damage to a sworn enemy increases by 10% (forest cunning). Avenger 4: All Forest Alliance creatures in the hero's army gain +1 to maximum damage.

It's just not very interesting if there are just bonuses like this.

The amulet could give an additional +2 attack (i.e., I didn't write it down, +0/+2/+4/+6).

In the proposed version, it shows that the Avenger skill itself becomes stronger, and if the number of abilities within the "Avenger" skill is reduced, we could somehow use underutilized skills by modifying them (for example, the useless skills "Ashes' Favor" and "Barbarian Luck")