Awesome units/spells

[Amhazair]

Ghost Riders is awesome. Casting one or two is a nice (and cost effective) distraction for your enemy. And if you have the means to mass cast them (requiring rather steep 6D mages) you can utterly devastate your oponents empire.

Call Horror is similar in principle, but less reliable. One horror can fail to take out 'normal' amounts of PD

[Meglobob]

Call of the Wild - For just 15N gems you get a werewolf thug + 20 wolves if cast in a forest. The werewolf can summon allies as well 2 or 3 more wolves per turn.

Awaken Sleeper - The firbolg does it all, good leader, good melee thug, good sharp shooter, keeps the morale of your army up. 10N gems, a steal.

Black Servant - Etheral/stealthy/life drain, what more do you want for 5D gems? Equip with quickness/skull talisman or skullface to get a 1 man army stealthy raider.