The goblins encamped below the Dolven-view have become a great threat to the dwarves, driven by their overseers to greater violence than is usual for them.
'Now that we have weakened the defences of the goblin-camp below, we may soon be in a position to launch a full assault against them.
'Go down there and see if you cannot defeat a few of the goblins' overseers. With the strongest goblins out of the way, the weaker ones will be unable to unite against us.
'Much depends upon your success, ${PLAYER}. Be careful!'
Goblin-overseers can be found in and around the encampment Gazatmur.
Slagvi told you that the goblin-overseers must be defeated if the goblin-encampment threatening the Dolven-view is to be destroyed.
Wigfast can be found at his hiding spot near Gazatmur in the Great Delving.
You should return to Wigfast and inform him that the goblins' overseers have been defeated.