Harmony - Troop Symmetry

But why not 100% then?
You need to understand that "attack" plays a much bigger role in clearing the map.

This statement is not very obvious and has no evidence yet.

Nowadays, the symbolic 5-10% and an overpowered bonus on level 1 often provide more benefit than 30% attack, but without an easily accessible and convenient bonus. Because the skill is insignificant, and the perk is everything.
A 10/20/30% damage bonus is not very significant, but rather mediocre, as it does not apply to ranged units. And defense works more effectively (an expert reduction of 1.43 times instead of 1.3), especially in popular tactics such as "shoot them down" (where damage is dealt by ranged attacks, the rest of the troops endure, and defense works) or "kill with magic" (troops endure, and defense works).

Added after 11 minutes

Because "chaos magic" is the elements of "earth," "water," "wind," and "fire" – the elements of the dragons of Asch. Renaming "chaos magic" to something like "elemental magic" would be more appropriate.

In the English version, it's not chaos magic, but destruction magic.

And before you change anything: you know why demons need "fire magic" (damage magic) when leveling up: 45%/10%/15%/30%

Chaos magic does not necessarily require high spellcasting; it depends on the balance of spells that can be customized (in the original Heroes 5, Chaos is indeed heavily dependent on spellcasting). There are also Chaos perks that are not tied to spellcasting.

Added after 10 minutes

Oh, distortion is definitely nonsense, but creation is like summoning, but broader.

Another possible synonym is creation.