[Taqwus]

You've got Death. Astral too, IIRC.

Death: permits disease, but unless your sieging commanders are also undead you may not want to bring in bane venom charms.

Astral: Pangaea is not a strong astral nation, so you may be able to use Mind Hunt. Use a spell focus to help beat Pan's MR. Not recommended if Pan has at least a single astral mage there.

If there are corpses, Carrion Reanimation may reanimate a bunch. They're poor at combat, but the sheer numbers might be helpful in battering the walls.