I could really use someones help with this. I've created two creature (or rather copied from the base game) and I want one of them to chase the other.

What I first did was to make them enemies by creating a faction each and having -100 for disposition. It kinda worked but I got attacked. Should I make the creature that attacked me be a part of the player faction or what? Lowering the aggression only makes the creature stop attacking the other faction and to be frank with you all the other creatures that does not attack are not a part of the player faction. Why should this be differient?