Playing in Challenging as Ceresa for the first time, I was really enjoying it and the game, and then Pariden declares war on me.

Up to then I was with a demon company, Ceresa and those Spear brothers. My cities were protected only by militia and guardian statues.

And then the game became a chore.

The AI would only send a continous stream of weak units against my weakest city (that was just in the corner of my most well defended city). Problems with the AI that were extremely annoying:

1) The AI cheats and always knows which is the weakest city you have, without scouting or scrying. This breaks immersion. And is annoying.

2) As it always knows your weakest city it sends a weak army after weak army, doesn't matter how many of them you destroy

3)As my strongest city was just besides it, I could reinforce it turn by turn with Ceresa, that alone could wipe any of the armies the AI was sending even with  Queen Procipinee, that was leveled by the AI as a warrior . (yes, as a warrior. It could be a sensible option if you had found early a powerful armor or weapon, but this wasn't the case)

4) The obvious tactic, if I was the AI, was to hit hard my strongest city. If it fell, the others would soon follow. To reach this objective, it would have to wait some turns and send various armies at once, instead of sending the annoying continuous stream.

5) I had another frontier with Pariden, with some barely fortified towns, that was never attacked. I could concetrate all my forces on the same side forever

I hope this is a good feedback of the behavior of the AI. It is impacting the game in a bad way, turning a pleasant experience in a chore.