Making disease or making monsters?

[Rango Swango]

Long story short I have been playing an evil campaign as a rakshasa lich with some friends after work, and I currently need to kill an entire country. I already have a zombie army and moving giant tortoise base, but now I need to decide how to destroy everything. I'm between implementing disease and plague to just wipe out the living populace with cancer mage, or trapping people the come to my arena ( in side the tortoise) and turn them in to monsters and more undead to overwhelm all the living. Not really sure how to experiment on people so I don't know what to do about the second choice. Just looking for input or ideas

[ZamielVanWeber]

Disease, but do not do half measures. Go to the Gray Wastes of Hades, slay the Oinoloth, sit upon the Seige Perilous and become the new Oinoloth, use powers to create an insane disease that kills people quickly and revives them as undead. Et voila.

[DrKerosene]

Is your typical "Wightpocalypse" not a valid option? I don't think a bunch of Wights, Ghouls, Ghasts, or Shadows would be that hard for your Villain to deal with.

Or do you want some kind of Mummy Rot based thing, where cities are left vacant and dusty?

Could some "living spells" (cloudkill and/or contagion) work for spreading death and disease?

I imagine a customized spell may be necessary, or a customized magic item to allow unlimited uses per day.