This may sound like a dumb question, but does the AC rise higher or go slower at different difficulty levels? I play on either Immortal or Emperor and I to find it hard to get the counter past 20, even when 4-6 civs on a small Highlands map converted to the Veil.
I don't know. I play on the same difficulty levels and the counter almost always reach 40. I play on standard maps, so that might be why. On normal speed.
In my latest Immortal Loss, os-gabella founded Veil, built Rosier the Fallen. The Prophecy of Ragnarok, and brought the AC to 40 before turn 170, after which she quickly declared war and took me out.