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Even though the topic is old, I also want to share my opinion:
Death
1) Skeletons are useless, even if you have 1000 of them; they fall quickly in a serious battle. Usually, even their ability isn't useful; vampires and a hero are enough.
2) Imps are very useful; they speed up the hero, steal mana, and can steal for the devils, so they can summon demons 2 or even more times. They are not intended for battle, except perhaps to retaliate. But the main thing is that they fit into the army in terms of speed with vampires and ghosts, so you can carry them around the map.
3) Zombies are the same as skeletons, only stronger; they are not that bad in city defense, but taking them into the army with their speed...
Nature
1) The Fairy dies like an Imp, but with her ability and speed, she is one of the best units. You can take out as many zombies as you want with just one fairy. And she can quickly scout the map and collect resources.
2) The Wolf is so-so; it is slower than many in its race and has no place in the army. Let it accumulate in the castle; the damage from two attacks is quite decent.
3) Leprechauns are only needed for luck; you can summon them with a spell, but they have no place in the army. (I think it would even lose to a peasant without Fortune).
Chaos
1) Thieves are fast, there are many of them, and they are created to steal resources, not to fight. But there are so many of them that they successfully absorb attacks at the beginning of the game and hit quite well. As fighters, they are somewhere between skeletons and squires in strength.
2) Orcs are one of the best if you get accuracy; otherwise, they are only normal up close, but they often help in city defense, especially with stunning in Equilibris.
3) Troglodytes have good stats, but they are slow, and you can't accumulate many of them, and their ability is practically useless, so they are almost irrelevant.
4) Pirates are also almost irrelevant, except perhaps on maps where the action mainly takes place at sea; then they can be useful.
Order
1) Halflings are good archers with accuracy and their growth; they are the main striking force at the beginning of the game, and later they defend the city well; their ability helps against Chaos Demons and other powerful monsters, but they should be sent to the garrison as soon as possible from the army due to their speed.
2) Gnomes are needed to cover the Halflings at the beginning of the game; then they just sit in the castle. However, if you accumulate 1000 of them, you can take them; their stats are good.
Life
1) The Squire, like the Gnome, is needed to cover the archers; the rest is the same.
2) The Archer, like the Orc, is very useful, but even without accuracy, the main thing is not to let the enemy get close to them, or it will be bad... but in general, they can play throughout the game if you don't lose them.
3) The Peasant, like the Thief, is needed to support the economy, not for battles. If their dwellings meet, the question of whether to take them or not usually does not arise, but only in Equilibris, where taxes have been raised to 2 per day.
Might
1) The Berserk would indeed be the best if it weren't for its uncontrollability. In my opinion, it is better to just accumulate them in the castle; by the end of the game, under the leadership of a tactician or mage, you can strengthen them so much that they will be very effective.
2) The Centaur is the most balanced of all; it is a good fighter for city defense, fights well up close, and has a lot of health. But they don't act as cleverly as fairies or thieves; they are just a strong fighter.
In summary, for level 1 units, you can distinguish several groups.
The best for supporting others are thieves, peasants, fairies, and imps, but they are physically weak and are quickly defeated. But their relevance can be throughout the game, not just at the beginning.
As combat units, the best are Berserks, Centaurs, Orcs, Archers, Hobbits, and Wolves are also good if there are artifacts for speed.
Leprechauns, Gnomes, and Squires are slow meat that can help at the beginning, but they don't bring much benefit later. Unless there is a free slot that you can't fill with anything else. But they are not useless.
Skeletons, Zombies, Troglodytes, and Pirates are the most useless. Especially the pirate. It is difficult for them to find a use; if anyone explains when they are useful, I will be happy to listen