Harmony - Troop Symmetry

In Heroes 6 and 7, this ability serves as protection. It will primarily protect against mages and rushers (the chance of withstanding the first attacks is higher due to the presence of incorporeality at the beginning of the battle – it’s like shadows hide units from the enemy, and they miss, but as soon as the units’ turn comes, they reveal themselves).

Added 17 minutes later
Regarding summoning magic and the idea of swapping the elementals – it seems a bit absurd, and I don’t particularly like it myself, but if we don’t do that, we’ll have to develop the elf through fire warriors, which seems like nonsense. We end up with two long branches: a life lord branch for the necromancer and a spell lord branch for the elf. The earth lord branch doesn’t have a logical development path.
It seems we’ll have to send the elf through fire warriors…