Arengar, I also leveled up Zehir with Light, Summoning, and Empathy skills instead of Combat skills in the campaign, and I invested heavily in the Leadership skill with a mentor. Zehir was flying through the levels like a phoenix. No enemy could cast a single spell because Zehir managed to cast a counterspell and cast spells for himself. Fortunately, there were no Necromancers with Combat skills among the enemies. But even if it's not possible to get Leadership on the map without a mentor, a mage with Light and Summoning is always combat-ready, even without Empathy and without Combat skills. The main thing is, there's no risk.