Finding the final creature on Elta's list might be trickier than it seems....
'As you were burning the corpses, I was thinking of what to call the worm. A bit tricky, but I believe the name I've chosen fits well: Bothin, named after an old hunting partner of mine who was lazy to the bone. You've already shown more competence than he ever did, and I am not someone who is easily impressed!
'Now, let's wait for Bothin to emerge. Make sure to keep its hide at least mostly intact; we'll want to hand that over to the Gabil'akkâ.'
Elta has suggested to wait and see if Bothin will appear.
Bothin has not appeared.
You should talk to Elta and come up with a different plan together.
Elta has asked you to find Bothin alone.
You should venture into the cave Skrizagáf, on the eastern side of Shataz-kordh.
You should continue looking for signs of Bothin in Skrizagáf.
You have found a dead Orc in Skrizagáf.
You should examine the corpse.
You should pretend to steal the Orc corpse and trick Bothin into emerging.
You have defeated Bothin and obtained its hide.
Elta waits for you outside of Shataz-kordh.