You appear to have come upon a trail of vengeance, left by a mysterious warrior whose deeds strongly resemble Thrymm's....
'These slain Orcs...they remind me of him. Alas that it cannot be! He is gone, and we are alone, but for this nameless warrior who slays Orcs in the north.
'It is a shame that this warrior cannot kill Núrzum. None of us can. Wildermore is doomed at last.'
Cyneberg is in the northern High Knolls, kneeling over a pile of slain Orcs.
You should speak with Cyneberg.