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

I'm planning to play Necropolis against the Orcs with a friend. I'll be playing Necropolis (as always:cool:). The map will likely be medium-sized, with or without a dungeon, but we always agree to level up to level 30 before fighting. Our skill levels are about the same, as proven in several scenarios. He claims he'll easily beat me, but I disagree, although I don't see any particular advantage for the Necromancers in this battle. To avoid mind control and other tricks, he's already warned me that he'll be increasing his magic resistance, especially against dark magic and summoning (knowing how much I like raising the dead + Kaspar + High Liches). This is 100% certain. So, I've decided not to rely on magic and instead choose a combat-oriented hero and draw the Orcs' rage and strength by forcing them to attack me. Possible options are Orson (most likely), Naadir, or perhaps Deirdre or Lucretia. After thinking about it, I've chosen this build, and I haven't fully allocated all the skills yet, but attack and defense will be developed exactly as planned. I'll focus on Light Magic if possible; I reread the article and realized that I'm basically on the right track. If that's not possible, then I'll probably focus on dark magic and summoning after all.