The Light:
Clockwork Golems: The first new unit you're going to see is the Golem, and you aren't going to miss it.The Golems are massive metal war machines created by the Dwarves. These guys can take a real beating, and can dish it out too. They may be giants, but don't think they play like Trow or Myrkridian Giants. Golems will kill just about anything with a single hit of their massive staffs, and are the best method for taking on large enemies or small groups. While Golems take very little damage from arrows, javelins, etc. they are very vulnerable to electric attacks and explosives. Golems can't be healed, so don't try it if you know what's good for you. Golems come equipped with several cannon charges. The Golem cannon is pretty powerful, and has a very long range, but has a wide damage spread, so be careful where you point it:)
Melee Dwarves: Melee Dwarves have green shirts and little black beards. They fight hand to hand with small but effective daggers, and have a number of satchel charges. While Melee Dwarves can't blow up the satchels themselves, they can still lay them for normal Dwarves to use. Trust me, you're going to need to use them on the higher difficulties.
Avatar Apprentices: Ah memories... anyone who played Myth:TFL remembers the Alric Avatar. Well think of the Avatar Apprentice as a weaker Alric. The Apprentice has a fast and effective melee attack, and can take a fair amount of damage. His real strength however, lies in his Dispersal Dream attack. Each Avatar Apprentice has a single Dream attack, and can decimate entire armies with it. Just remember though, you only start with one, so don't use it lightly.
Skræl Wise Ones: There is one Skræl Wise One in this story, and that's He Whom Fate Follows. Fate is the hero of our story, and as such is very useful. First off, Fate has a sling shot attack. Its range is a little less then an arrow, and its damage is a little more then an arrow. This attack is useful for picking off Wights or thrall, but wont do much to slow down a Maul. Secondly, Fate has a lovely little cudgel for a melee attack. Its pretty good, but I don't recommend letting Fate get into too many melee battles, because if he dies, its game over. Fate also has a healing ability just like Journeymen. As a Skræl, Fate is amphibious, and can move underwater at a very quick pace.
The Dark:
Skræl: Usually, Skræl are peaceful and honorable. But as you will soon find out, the Skræl aren't quite themselves lately. They have a Sling attack like Fate, but they aren't as fast or accurate with it. Likewise, they have a slightly less powerful melee attack. Skræl can move very very fast underwater, so watch out for fast moving ambushes.
Sea Elementals: The Sea Elementals where created by the Skræl long ago, but since the Skræl are being nasty, so are their creations. Elementals are big, powerful, and can absorb a lot of damage. The best way to deal with Elementals is to soften them up with some Dwarf bombs, then finish it with a Golem or large group of melee.
Mermaids: Oh la la, they gotta be the purtyest fish I've ever seen. Don't let their looks fool you though, they can really give you some pain. Their only attack is a short range lightning burst, but its very powerful. Never ever let you're Golems near them, or you're going to end up with a half dead Golem. Mermaids are the fastest thing in the water, but they move slower then a Wight on land. Lure them out of the water with a Melee Dwarf, and take her out with explosives.
There are more friends and enemies in this story, but if we told you about them, we'd have to kill you:) So go out there, have fun, and kick those baddies to the next age!