there is one necromancer in Kordar - hwo often has (not always) necromancers - apart of that I nearly never found necromancers sooner (when very lucky, than vampires in the swamps... but necromancers? pfeew... tough luck!)
Next stop if Kordar necromancer is not the lucky ace: Demonis -> there are very often necromancers for hire... If even this failes:
In the underworld (in elven lands) are necromancers nearly totally always (as this game is random in huge extend I would say that there might be 1% chance you won't find them even there... still I am rather optimistic)
Also you may reconsider if necromancers and shamans are totally so powerful as you see them to be.
For the orc ambassy : You need to win the orc battle to gain access to the recruit units - prepare for tough fight
