[mike128]

Ok-they should be smart as in the beasts should know when to fight and run away.
If they know they can't win they will run-if they know they can win they will fight.
Ambushes would also be cool.
Imagine walking around with your party-not a beast in site than boom-out of nowhere a large swarm of beasts appears and kill you and your whole party and devour your corpses.
Maybe you would sacrifice some of your party to escape.

Also beasts should all have skills and be able to set traps.
Maybe they could siege cities.
You know attack cities in large groups and smash walls and buildings without siege weapons.
And when the city is destroyed and everyone killed stay around for a few days to feed on the remains.
So invasions wouldn't be just some cheap event-would be more of a thing of life and death if you fail you die along with the whole city.

Also random beast distribution-very strong ones could be in the same area as very weak ones.
They would also migrate from 1 area to another so they would never be in 1 area all the time.

So players would have to move in large groups if they don't want to be wiped out.
This would discourage soloing-people that solo would be wiped out real quick.