Discussion of the Necropolis faction.

Sorry, I still don't understand. How can 8 ghosts stand there doing nothing but retaliating, the skeletons die, and all 84 guards die? What does it mean for a HERO to attack directly? With a SWORD icon? Can you be a little more specific? I haven't played like that. I'm interested in the very FIRST STARTING battle, but in more detail.
After all, the point of the ghosts is to heal. Are they actually healing?

No, the point of the ghosts is that if they stand where they appeared, they defend themselves and don't take any other actions (they don't attack, they don't move, they don't heal anyone - they just stand and defend), they take very little damage. And the damage they do take is healed by regeneration (a hero's spell, lasts for 5 turns). If the ghosts move, attack, or use a skill, they will start taking a lot of damage.

Direct hero attack - sword icon, yes.

Not skeletons, but skeleton (1). You don't need to put the others in the battle.