In the city of Ysa, I was approached by Ambassador Keen, who gave me the Uprising quest, which requires me to assassinate Ambassador Brenner. However, if I speak to Ambassador Brenner about it, she in turn wants me to murder Ambassador Keen. Since letting them both lives earns me no experience points, and I like experience points, that isn't a valid option for me and I seem to have a decision to make.
The only short term difference I see is that if I kill Keen, I'm supposed to deliver the daggers somewhere. If I kill Brenner, I'm supposed to dispose of the daggers. They're lousy daggers, so what happens to them doesn't particularly concern me.
Does the decision over who to kill have any impact on the overall story or future quests?