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I almost completely disagree with the choice of heroes.
Ilaina is a waste. An extra fifty peasants at the start doesn't really give you much. "On large maps..." but what about large maps? Are you going to rely on peasants or militia on large maps? Will that be your ultimate army? And who will be your archers? The basic growth? Don't make me laugh. "On large maps" - Axel, Laslo, Dugald, Rutger. And no Iris. You'll upgrade to Griffins anyway. If the map is small and you don't have time to upgrade, there won't be many of them.
Sylvan - Dirael is awesome; try shooting a volley of enchanted arrows that not only deal great damage to the Hive but also push the enemy back a few spaces on the initiative scale. Plus, it really helps with clearing mines at the beginning. Does Anven increase damage with levels? Learn your facts. It increases damage to sworn enemies, which is very difficult to implement.
Talanar is terrible. Fury is garbage. And starting with a ballista doesn't give you anything without the corresponding skills.
Dungeon - Sorgall is an excellent hero. With the right skills and a bunch of Furies split into different stacks, attacking the enemy next to a Lizardman, he's just amazing. Although the ability is certainly specific.
Erin is not a clear-cut leader. The ability to fire additional witches when casting a spell that hits an area is such nonsense that it's better not to even think about it.
Academy - neither Nazir, nor Maahir, nor Nura came close to being "champions." Ora, on the other hand, is an excellent hero, possibly the best. Razazak - if you're perverse. Faiz - if you're a terrible pervert. And all that mana regeneration in battle is just garbage. Why would Academy heroes need to regenerate mana when they already have so much?
Inferno - Deleb is not a leader. She's been severely nerfed, and I have no respect for the developers for that. Her ballista now just shoots... forget about all those tricks with fireballs after level five. IT'S NOT WORTH IT NOW.
Nimus - this is an excellent choice, as are Grog or Marbas. Nibros - explain why he's good? Say? No, he's not. 1 luck plus canceling tactics is a negligible ability. And it doesn't increase with levels.
Necropolis - not Naadir with ghosts. Kaspar, with his overpowered plague-tent rush, and Deidra with her overpowered scream.
Dwarves - Karli, Ibba, Ingvar(?). The most optimal choice, in my opinion. And don't be tempted by things like "learn a rune when leveling up" - it's not worth it.
Well, Helmar is also very good.
Orcs - Tilsegg, Argat, Goshag (xD), you can also choose the King of Wyverns.
That's it.