They definitely are aggressive, I've seen monsters destroy a giant cluster of 3 outposts at once and even a city owned by AI players, but yes, they don't always attack. To be fair, AI monsters don't always go after YOUR stuff either. I guess that's because monsters don't always behave logically? They might just wander around and leave, although if they are dead set on attacking, they'll rush straight for your city. The reason you are probably thinking this is because the AI doesn't clear monsters very well currently, so it leaves a ton of them hanging around, only one or two of which might be aggressive (but you don't notice because of all the other ones just hanging around). Where as, if you clear everything out (like a player would do), the aggressive one is always clear as day.

As for the chasing pioneer thing, when the pioneer "builds" the city, the monster see it as being destroyed, and it needs to find something else to do... perhaps it doesn't think it should attack a city with militia defenders? *shrugs*

Neutral monster are aggressive to AI players, but nowhere as aggressive as they are to players. I have game which I have place an outpost next to a monster nest. Within 100 turns, it was destroyed. The same scenario by AI players, 300 turns  later, their are still standing next to the nest. I notice monsters go after AI player's resources rather than the outpost. Also I have starting to treat neutral monsters as a separate fraction that allied with all AI players, and bonus when they destroy AI players stuffs.

I was ranting earlier because I got a chance to cast Shadow World spell, which summons demons into the world. I feel that it is a neat spell, but with neutral monster doing almost nothing, I do not know the purpose of the spell. My idea was to bring destruction to nearby AI cities, but it looks like it is to use for champion xp farming now.

The non-aggression of mobs to AI units and overt aggression to players units means they effectively act as guardians for the AI, so why would they want to clear them?

Example:  A death demon with a pack of assassins next to AI city ignoring AI units.  Player army arrives and captures AI city, death demon group immediately attacks captured city on same turn, destroys players army and razes city.  Next turn AI pioneer builds outpost in the same area next to death demon group which ignores it.  A few turns later next player army arrives,  gives death demon group a wide berth, and captures another AI city.  Death demon group uses road link to arrive at captured city next turn, destroys player army and razes city.  AI builds new outpost on the same spot.  Player gives up.

personal, I don't think monster should raze city, maybe hit population or even hold city (but monster don't use it but  hold ing as thier home ) then we can take city back and if won, then repair city for few turn, would be nice rather than raze city then you can't build that city spot again, monster ruined it. I did clear all monster that huge area, then this huge spider out of nowhere raze my city, I kind of piss and not fair, not know spider out of nowhere, while I did work and clean readly, real good job, but this spider come out of "nowhere" ,if spider do come, that spider much come very, very long way to raze my city, arrrr.

And I'm sure this will re-balanced.  FE's a work-in-progress.  It's not really the kind of thing that needs to be pointed out to Stardock, but it is odd enough to draw comment from us.

This has been my experience, so I play around it.  Of course that means I am basically playing a different game than the AI is playing.  I'd rather that both play the same game.

It is truly noticable that monsters are definitely aggressive to the human player and not so much if it all to the AI player.  

This is a spectacular game, and games this good can not have issues this silly. I get that the neutral monsters are at the core of the idea of the game. That they should treat the human player different than the AI player is not acceptable in a game of this calibre. I have read some good idea, but more to the point, consider this.

On the easiest setting neutral monsters should never or almost never bother the human player. I don't play on those settings, so perhaps it is this way already. On medium, or neutral, or what ever the setting is called, the human player and the AI player are supposed to be on even footing. Even footing! When I watch a huge stack of neutral AI monsters sit right next to the computer AI controlled town for hundreds of turns, then destroy it the turn after I take it, that is not on an even footing.

So for crying out load, make neutral monsters treat the human player and the AI player the same, at least on normal. Harder settings? That is a different can of worms. I see no reason why neutral monsters shouldn't be meaner to the human character. Still be careful though, because we all know there are some monsters at the very beginning of the game that no army can touch.