[Nerwen]

Now, let's see... the talk of "harming" and "filling souls with fear" suggests something bad... but perhaps Urwen is being sneaky.

So perhaps it's the sword Glamdring, addressing the Great Goblin?

You and your companions are alarmed
Your soul is filled with fear -all the goblins in the cavern were freaking out
Only you shall be harmed
By me, ere I disappear. -Gandalf bisected the Great Goblin, before sheathing his sword.