Food for thought!
The ability to poison foods.
Just a quick thought I had. You should be able to poison foods and you can trade them to people you don't like. There would be a skill needed and perhaps x number of points in stealth to detect the poison. Different poisons would do different things.
Such as one might make the haven guy dizzy & collapse on the ground where as another one might not be strong enough to murder, but to slowly drain a persons life & they would then have to obtain certain materials in which to make an antidote to recover from the said poisons.