My stats at level 18:
9100 Leadership
13 Attack, 23 Defense, 11 Int
Ok, back to story time. Instead of pushing to Castle Bogacho and weaving around the overpowering heroes, I instead went back to Darion to restock my troops. While I was there I absolutely creamed Archmage Rezo (it felt great) with a Geyser + Underground Blades on turn 1. My reward was 14 more Inquisitors.
I also killed Big Pato in the arena, and upgraded my baton from the lowest level up to General's Baton (+750). The extra 650 leadership puts me at 9100 which didn't change the enemy army status (still overpowering) but I am a little bit stronger. More importantly, my army stacks are above the enemy demonesses charm capacity so I should be able to clear some of the tougher demon armies now without taking ridiculous losses.