Reinn never made it to the Twenty-first Hall to deliver his news to Mögr. With the dangers of Zelem-melek upon his path, you cannot help but worry for him.
'If you are worried... perhaps I should be as well. I hope you find Reinn and send him back. I do miss the foolhardy fellow.
'I promise I will do better and listen to him. I believe that he was not wholly wrong to be so guarded.
'Please return with Reinn, ${PLAYER}!'
Reinn tried to get to the Twenty-first Hall from the Great Hall of Durin.
You should backtrack from the Twenty-first Hall and search for Reinn, heading south and taking a right along the passage.
Ozût mentioned another Orc involved in Reinn's death.
You should search the passages to the Great Hall of Durin for clues to Khîl's whereabouts.
It is likely that Khîl made his way to the high platform overlooking the centre of the Great Hall of Durin.
You should search the high platform for another sign of Khîl.
Mögr has followed you to this spot, and stands nearby in silence.
You should speak with Mögr.