Welp, i finished the whole age of fear series so far so here is my thoughts.
The first
Age of fear: the undead king. It's going to get a gold version in the near future, which will add the open world from the 2/3 games and bases(from what i heard)
Humans are basic, but have all of the bases covered. You have healer monks, double damage blademasters, high damage ballista, mobile and tanky knights. Wizards won't impress you with original spell list but they're tremendously useful. Their only weakness i noticed is the lack of high hp units, the only one they have is a vulnerable to electricity knight/paladin. Something like a pair of dwarven tesla gunners can make a short work of them.
Undead are fun, especially once you start getting stuff like the bone catapults, bone golems and plague zombies(this ones will quickly lose their usefulness tho). Necromancer is their key unit and his rise dead spell can do two things:
-Revive the enemy corpse as a cheap and expendable skeleton, the skeleton type depends on the enemy type
-Revive at full hp your fleshy undead types like abominations or vampires.
So your usual tactic as them is to slowly overwhelm your enemy with the group of constantly reviving ghouls/vampires and once you start inflict casualities overwhelm them with your skeletons. I like pulling this bullshit against enemies, but hate it than the game pulls this against me.
Age of fear 2: the chaos lords
Demons are fun and suprisingly diverse. A lot of your units have a fire strike(80% to +1 fire damage). You have beholders with a ranged paralyze attack, cannon that can hit up to 5 targets inside it's range, body possessing will-o-wisps. Mancubuses deal high damage and have a lot of resistances, but are clumsy(can't walk and attack at the same turn), succubuses have a very useful spell list and can hold their own in melee. Summoners/demonologists/Chaos mages can summon some very useful and expendable demons(especially once they reach an elite rank), but they start the battle with no mana.
Orcs have a strong melee/middle range in the form of ogres, black orcs and troll throwers. One of their leaders also have the bonuses towards an avaliable army size. Shaman can hypnotise enemies and goblin kamikaze is just plain amazing. As a weakness, they tend to have a limited ranged and spell damage options, goblins are very fragile and their death can quickly cause a morale loss. Guys like ogres tend to be very vulnerable to ranged damage and poison.
Age of fear 3: The legend
Forest folk feels a bit similar to the humans in the sense that they have all bases covered(with the exception of artillery). The have a lot of choices in their army composition. Saproling/Ents can root the enemy on attack(doesn't need to hit, the enemy will be rooted even on miss), have a lot of hp and regeneration, but they're vulnerable to fire and they have a low attack stat(low chance to hit). Insectoids are alternative frontliners with a fire resistance and both of their evolution options have some fun abilities, they have low morale however. Fungusoids with the posion immunity and poison arrows or more long-range driad huntresses with the crippling shot. Driad/Nature sorceress can heal, turn into bear or transform the enemy into the pig. Anti-undead holy aligment unicorns as a cavalry or evil aligment driders as an alternative(which you can't hire in the campaign, you only have one as a hero). Their plant/mushroom types tend to have/can learn a regrowth ability, which means that they don't die even if killed. You also have vampire mushrooms and dire bears, and i heard that the developer plans to upgrade their roster in the near future.
Dwarfs are quality over quantity race. Their units tend to start with some outrageous abilities, which for the other factions would be a high tier upgrades. Like the precision on dwarven gunners/rogues(ignore defences above 3) or engineer starting with 3 shots of flame breath. All of the dwarves are prepared to chug ale at the moment notice which heals them, removes posion and makes them immune to hypnotise spell at the cost of some stat penalties. All of the dwarves are tanky and they can compliment their army composition with constructs like arrow resistant animated armors or super mobile but vulnerable to magic guardians who can shoot a fire laser, they also have super long range aoe damage cannon. Their weakness is a generally low speed, lack of cavalry, a proper long ranged sniper and a proper spellcaster. Runemaster's runes are strong, but they're all are one use items and so he will quickly become a deadweight in a protracted engagement. Dwarves are also expensive and their leaders are grumpy(-1 army size)
All in all, a solid fantasy tactics game as i said before. Earn the loot from fights, develop your squad, choose the equips for your heroes - you don't need to do much to make a men happy. If interested, you can try the
Age of Fear: The Free World, a free version of the game with the open world and no campaign missions. You can choose here your own hero, like the animated armor.