Amaan the Wise at the Temple of Telhamat in Hellfire Peninsula wants you to return to Sedai's Corpse, northeast of the Temple of Telhamat, and use the Seer's Relic at that location. Return to him after you've completed this task.
I hope the vision you witnessed helped you gain some perspective on Sedai's death. The relic showed you a likely series of events leading up to the present. The truth may have been different, we'll never know for sure.
Would you act differently knowing what you know now?
Who can say whether our conflict with the orcs will continue? What's important is to remain open to the possibilities.