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

Against Orcs, darkness is essential! But you can also try one of the light magic spells – Divine Retribution (which doesn't depend on the spell itself!). At the beginning of the battle, cast Plague or something else to reduce their rage, and then bombard them with Divine Retribution, as Orcs deal very high damage! In short, you can defeat the enemy with its own weapon! Where can you get Divine Retribution? Of course, in libraries, which are often found in the map generator!