[Shadowcran]

The Wolf Riders are a collaboration between the Military dept and the Research Dept. You need to get Elven Cedar, which is at the end of Aralan conquest(late in the game) and some item from Dragandor. After that, you'll be asked for a lot of prisoners to turn into the riders, then 100 wolves(witches usually have them). I only recently(2nd playthrough) started trying them out and they're pretty good. Here are the stats:

Name: Orc Scouts
Level 4
Leadership 200
Attack 24
Defense 32
Initiative 5
Speed 3
Crit 10%
Damage 10-15
Health 180

Talents-
Piercing Strike-12-18 physical damage and ignores physical resistance
Support- Select another of your troops, Without using Action points, the Orc riders fires at same target as that other troop. Does 6-9 damage to that target regardless of that distance, lasts for 3 turns
Companion-Summons a troop of Wolves each having leadership 150. 132 of them was producing around 533 wolves.

Abilities:
Of the Dark
Shooter
Crossbowman
Wolf Cavalry
Greed
Adrenaline

The Metamorphs suck, take my word on it.

The Spy is currently bugged for steam players. I haven't gotten them and there's no prompt to do anything else to obtain them. If someone could post their stats I'd sure appreciate it.

The Female Vampires make little sense and for the reasons you highlighted. I did read though that you can spam the spell "Armageddon" while using the female vampires "Transformation" ability. They take no damage from Armageddon while in this mode.