Heroes 5.5 WarGame Edition - Tactical Edition.

Is Northern Breath not Frost Breath from the unused abilities? If so, did you change it somehow, or did it originally work the way you described?

No. Technically, it's an empty ability that does nothing, to which a 2x2 pattern attack is linked, dealing 50% damage to secondary targets.

I've been borrowing new peasant models and icons for a long time, but I haven't fixed the animation problem yet; I haven't had the time.

Added 6 minutes ago
Regarding the gremlins, we discussed it and decided that it would be better to give them the Ammunition Steal ability instead of Flame Strike. And spirits don't need it (they have an interesting retaliatory ability with incorporeality). Configure the ability so that it works almost across the entire battlefield, so that ranged units don't have any particular problems using it.

Added 2 hours 18 minutes ago
For the Nightmares, I made the following changes:
- Gave the Blazing Nightmares (upgrade) the Withering Aura instead of Charge.
- Gave the Ash Nightmares (alternative) Charge instead of the Withering Aura.

Now, the upgrade is Fire Skin + Withering Aura (focus on magic damage), and the alternative is a combination of Charge + Intimidation (two random abilities).

Added 2 hours 30 minutes ago
I also changed the upgrade and alternative for the ghosts:
- Gave the Shadows (upgrade) Retaliation (instead of Charge and magic vampirism).
- Gave the Spirits (alternative) Magic Vampirism and Regeneration (instead of Retaliation and Ammunition Steal, which went to the gremlins).

Charge is not that interesting for the ghosts in general, as Regeneration, which they had since Heroes 3.

Added 3 hours 34 minutes ago
I'm thinking about the following option for the beasts:
1) Return the Raiders the ability Return.
2) Make the combination of Return + Retaliation typical for all 3 types of beasts.
3) Beasts: +Wound (guaranteed debuff that reduces speed).
4) Furies: +Agility (increased defensive bonuses for movement).
5) Megeras: +Dark Strike (chance for a random powerful debuff).

Comments:
1. The combinations of Return + Armor Piercing and Return + Heavy Class have always been interesting for the lizardmen; it was because of this ability that they were once called Raiders.
2. Return is a typical ability for all types of beasts, but when adding it to the lizardmen, it is necessary to additionally highlight the beasts, and the general Retaliation for all is perfect here ("ranged" units at short range).
3. The combination with the retaliatory Wound makes the beasts especially interesting; on the one hand, they are similar to Spearmen (Retaliation) and Javelin Throwers (ranged attack), and on the other hand, they have fundamental nuances (unlike Spearmen with Beast's Vengeance, they don't rush into battle and act from the back rows, and unlike Javelin Throwers, they don't work at long range). And in terms of physics, the Beasts will have a traditional advantage in speed, initiative, and damage, while the Spearmen will have colossal survivability. Thus, the units should not become too similar.
4. Perhaps, instead of Agility, something else should be invented, but I want to test the operation of this combination with Return. So far, without practice, it is difficult to immediately say how strong the synergy is here and whether it is worth it.
5. Previously, the Megeras had Spell Strike, but now this feature has become unique again for the Daughters of the Earth. At the same time, it is possible to play out a weakened random version of this ability with the "short-range" Megeras (Return + Retaliation). But probably, it will be necessary to add Charge to strengthen the synergy.