You fought the trolls of Urugarth with great success, but the leader of the Gertheryg remains a threat.
'I can see why you were sent all the way up here to help us. You did a commendable job back there against the trolls, but there is more work to do.
'The Gertheryg of Carn Dûm are commanded by a vile fiend called Barashal. You must go there and slay him.
'Barashal won't go down without a fight, so be sure to rest well before you head out west into Carn Dûm.'
Barashal is at Carn Dûm, to the west of Tármunn Súrsa.
Táni was impressed by your efforts to purge the trolls from Urugarth and has sent you on another mission: to defeat Barashal, the leader of the Gertheryg.
Táni is at Tármunn Súrsa, to the east of Carn Dûm.
You defeated Barashal, the Lord of the Gertheryg, in battle and should return to Táni with the tidings of your success.