What skills should Necromancers take when facing Orcs on a very large map?

Darkness, darkness, and more darkness! Even when completely suppressed and with a full set of dwarven artifacts, it remains a plague for the Stronghold. Leadership – forget about it!!!!!!! I don't really understand why it's needed for the Necromancer. You could also try Light in addition to darkness + the Twilight perk (if you have castles with Light magic). Warriors will be greatly strengthened, and most importantly, it's unlikely that the Orc will be able to suppress Light, and resistance won't help either. In my opinion, the only choice for a late-game hero is Lucretia!!!!!!!!

Added 5 minutes later
Defense (until the last battle)
What for????