Old ruins of ancient civilisations predating Rokugan.

The person in charge here is Iuchi Hira.

They have a little model of the city which they are building.

There are many places in this city which has traps and nasty things. There is an infestation of minor things such as Mujina, serpent shaped things (not Naga), ghosts, floating heads, etc. Some people have vanished, then their tortured and mutilated bodies were found later.

We are taken to where they have some strange wall carvings.

There is a very accurate map. Lots of detail on it which isn't on the Imperial maps. Several diamond markers, not sure what they represent.

A Diamond in the shadow lands area is probably where Volturnum (Oblivions Gate, where all the spirits came through) is.