Deep in the Mokál Rukh lurks a particularly dangerous colony of nerbyg. The Conquest of Mordor requests an adventurer to go and defeat them.
A bounty notice is pinned to the board, stamped with the royal seal of Gondor:
'Wanted: The Frenzied Norbog
Deep in the Mokál Rukh lurks a particularly dangerous colony of nerbyg. The Conquest of Mordor requests an adventurer to go and remove them. Defeat the largest among them, The Frenzied Norbog, as well as many of their number.'
The frenzied norbog and other plague-ridden nerbyg can be found deep within the Mokál Rukh, behind Seregost.
You should defeat the frenzied norbog and other plague-ridden nerbyg.