So she wants you to start a war between the two of them and hopes that will kill them off quickly. She will tell you that she is tired of the rival clans that are in the area.
Borderlands Walkthrough Part 49 – The Dust Sidequests: Clan War: Starting the War, First Place Starting the War Once you get this quest from the Sanctuary Bounty Board head out to the Dust and talk with Ellie.