Velusion certainly surprised me in another game we're playing in Middle Age. I had a game against the AI back in Dom2 when I never saw anything from Ermor except the insanely high troop graph until it was almost too late and the first two armies composed each of 2k undeads came and hit my provinces - I was doing fairly well before. Before that, I was sure of winning, at that moment I was close to defeat and I only got the upper hand back by bringing up the Eternal Pyre and forging Flambeaus like crazy. The game was getting quite interesting because of the sudden change, as I only had about half a dozen Dom2 games in total and I was totally unaware of the situation before. So, I was expecting this type of game with hundreds and thousands of undeads in Middle Age, too, for which I soon prepared temples, priests and spells of mass destruction like Earthquake, but I got hundreds of Principes and Shadow Vestals instead - high defense units which I have to fight in totally different ways because I can't even hit them, and even if I do, I'm not doing much damage because they either have good protection or etherealness.
I don't know how to surprise somebody as LA Ermor, but it might be worth a try to think and play outside of the box.
EDIT: Aleph, I might be wrong, but I think that unless Ermor, R'lyeh's dominion does not kill the population in provinces that they don't own, it "only" makes your commanders insane. Then again, you should either make sure to have dominion in your provinces where your troops are, or not have any troops in there at all. I also believe that the effect from R'lyeh is not as strong as from Ermor when it comes to decimation of the population. And freespawn from R'lyeh are still humans or atleast humanoid, so they suffer from fatigue etc., unlike undeads. Maybe it's because the insanity thing is an added disadvantage for R'lyeh and kind of a funny effect, too.
