Darri has been wondering about the purposes of the ancient mirrors of Moria.
'Greetings, friend ${CLASS}. I am Darri, and I hail from the Lonely Mountain. It is hard to believe we are truly treading the ancient paths of Khazad-dûm, is it not? It is enough to kindle a flame in the heart of even the stoniest dwarf.
'There is one thing in which I have a particular interest: the mirrors you may have seen about the Twenty-first Hall. I believe there are four of them, and I have a theory about what they are for.
'Could you go and record some information about the mirrors, such as rotation, location, and so forth? I would like to study what you find.'
The four mirrors can be found at the corners of the Twenty-first Hall in Zelem-melek.
You should find the mirrors and record the rotation and locations of them.
The dwarf Darri can be found in the Twenty-first Hall in Moria.
Having found several unbroken mirrors, you should return to Darri and report your success.