Use Wraith/Shadow pits under your cities for optimal destructive power. - One of your best bets for exponentially scaling armies is an army made of wraiths or shadows made from bunnines<sup>1</sup>. When released, your army of undead bunnies can convert a city into *even more wraiths* quite quickly (in a matter of minutes or hours, depending on city size) Looking at the [Necromancer's Handbook] [1], your best bet is to go Cleric/Master of Shrouds. While Create Greater Undead can simply create Wraiths under your control, A Master of Shrouds/4 (achievable at a quite respectable level 8) can summon a wraith.) So long as the wraith kills another creature (again, remember your safety-circles), you can dismiss it, and rebuke undead that newly created wraith until he's under your control. Use this as the seed of your large armies. At level 9, depending on feat and domain selection, you start with: "At any one time, the cleric may command any number of undead whose total Hit Dice do not exceed his level." Therefore, ignoring bonuses, you can, at level 10, have two wraith generals. On [further reading][2], you can also have a nice skeleton honour guard with wraith army if you delay a few levels and enter into this via [dread necromancer/8.][3] Repeat once or twice in each city you want to destroy, ensuring that the wraith pits have good (secure) triggers and a steady stream of living creatures. The only real problem is that: "Wraiths are utterly powerless in natural sunlight (not merely a daylight spell) and flee from it." Which means that one wraith isn't simply a continent-killer. Still, if you set off one of these traps at sundown, it should trivially kill the city. The circle of death will expand by how far a wraith can travel between sundown and sunup, and how many of them can hide from the sun during the day. Why Wraith Pits work - [Wraiths][4] have the ability: >Create Spawn (Su) Any humanoid slain by a wraith becomes a wraith in 1d4 rounds. Its body remains intact and inanimate, but its spirit is torn free from its corpse and transformed. Spawn are under the command of the wraith that created them and remain enslaved until its death. They do not possess any of the abilities they had in life. Shadows have a similar ability and are creatable earlier, but are weaker. Therefore, so long as you create a set of... well... Nazgul as your undead generals and maintain control in any of the usual ways, they can grow their numbers exponentially governed by the speed of input. I do recommend confining each general (and his army) inside a fairly small magic circle versus evil under each city. Feed them as necessary with rats or bunnines (depending on your sense of style). When it comes time for invasion, break the circle. Remember, incorporeal creatures don't have problems occupying the same space. Use this to your advantage to "overlap" wraiths in your pit, such that a small pit can have an insane amount of evil inside (make sure the circles play a nice da-DA-da-bling when exposed to light, much like the shipping containers of modern intel NUCs). This method will tend to create a lot of undead "radiation" as higher-ranked undead are killed before their spawn. These uncontrolled undead will infest the cities they have been released in and make them a pretty fair "no-go" zone for any kind of living life. This plot actually lead to the campaign world of one of the games I played in. The DM is writing a [web-serial set in that world][5]. <hr> <sup>1</sup> Bunnines have been chosen, because the only thing scarier than an undead abomination trying to eat your life force is a once-cute incorporeal bunny abomination. Use any quickly multiplying resource. Consider chickens or rats. I'd recommend Algae instead, but I'm not sure blue-green algae gets a constitution score. If it does, and you can figure out how to illuminate it for optimal growth rates, you can be quite quite scary quite quickly. [1]: http://community.wizards.com/forum/previous-editions-character-optimization/threads/1049211 [2]: http://community.wizards.com/comment/20768526#comment-20768526 [3]: http://community.wizards.com/comment/20768526#comment-20768526 [4]: http://www.d20srd.org/srd/monsters/wraith.htm [5]: http://newvalenar.wordpress.com