To Blood Magic, Or Not To Blood Magic

[quantum_mechani]

Goblin said:
So the answer is have undead (no maintenance and no moral checks) or wipe out their capacity to produce enough blood.
I have noticed that the AI has a fondness for suicide battle groups - ie an army will attack a new place each turn, moving deeper into your territory. This is usually quickly fixed but often blood hunting grounds come under threat. Is the AI actually trying to capture these or just taking an offensive strategy?

I'm almost positive it is random agresssion.