'Kergrim are disgusting creatures, feeding off the rotting flesh of the dead. I think it should be one's duty to destroy them. Nothing good can come of such behaviour.
'Look for Bonetooth and Old Gnawer, both kergrim. Find them and slay them so they can no longer perform their vile acts upon the dead.
'You will find them in Skumfil to the south-east of the Shadowed Refuge.'
Skumfil is nothing more than a dumping ground, a place where the fallen Orcs of Moria are discarded when they begin to reek. It is here that two foes have gathered, each intent on using the corpses found therein for their own purposes. The kergrim and other ravengers as a source of food, and the insects as a place to lay their eggs to spawn future generations.
Defeat Old Gnawer
Bonetooth and Old Gnawer are within Skumfil, south-east of the Shadowed Refuge.
Odmar wants you to put an end to the kergrim-leaders who brought the corpse-eating creatures through the tunnels of Moria to Skumfil.
You found the two kergrim, one ancient and the other a summoner, and destroyed them both. Odmar, at the Shadowed Refuge will be pleased to know that this is done.