So here we are, Lord Carrodus, locked up in his castle. It has walls... and it has an Epic Herostack, and it has free defenders.
Epic Herostack. Oh, yes, the one that can smash armies with ease right? Right?
Before we begin lets settle some ground statements
1. They all rushed forward and were casting offensive spells like Storm to do damage.
2. The AI got like 3 turns before I could even move, their initiative bonus was MASSIVE.
Ok.
So on turn "3" I cast Battle Cry with my single Hero. I have brought an army with me consisting of longbow armed plate-mail armored female archers, with supporting traits (Accuracy, bloodthirsty and fast). MY hero's specialisms are Air and Life. This is not my sovereign. He cannot hit very hard, that's why he has brought the archers. These are a relatively new design, but I've levelled them to 13 already ( Was fairly quick tbh). They come in unit size 7.
So here we go.
Turn 1, the AI rushes forward, casts Haste on some units.
Turn 2, the AI rushes forward a bit more, some of my troops take some damage. I mean, we're talking about the 50 or 60 damage per hit variant, so some lots of damage.
Turn 3, More damage.
Turn 3 - mine, I cast Battle Cry, +2 Initiative all around.... my archers move up in the que, by miles.
Turn 4: General Carrodus and his 150 HP are pincushioned.
Turn 5: I take more damage, pincushion more units, cast Storm.
Turn 6-10 repetition of turn 5, with less enemies. I cast some healing spells to buff up the army. *yawn*
End result: I did not loose a single unit. Most of my ladies lived to tell the tale. After the initial rush Turn 1-3 I feathered the opposition with ease. Why did I survive?
Because even if you do 60 damage AoE style on all 7 of my units, its just a scratch... unless you have 6 heroes all with Maul, a set of 6 of these units with a life-caster with Battlecry is a match for anything.

596 HP... per unit... *grins* and all that because I made a small lap around his cities, killing off some monsters. Make no mistakes folks, once you get up that tech tier and have those units, the war will start for real. As soon as the hero-speed-levelling is done, you will love units... because they are so ridiculously strong.