Daervunn has warned you of a new threat to the north near the entrance to Ram Dúath and that maybe it is the Knight you seek.
'Golodir sent you? That is well, for it means his spirit has been renewed.
'There are grave dangers about and many have spoken of a new evil from Angmar near the entrance to Ram Dúath. I am quite certain that this is the Knight you seek.
'Go to the entrance to Ram Dúath, and you will find him...but be wary, there are many Angmarim in that place. It will not be an easy path.'
The Knight of Mordirith may be found near Ost Crithlanc, north-east of Esteldín.
Daervunn told you of a new threat in the north, which may be the Knight you seek.
Daervunn is at Esteldín, south of the mouth of Ram Dúath.
Having defeated the Knight of Mordirith, You should return to Daervunn and let him know of your success.