I still can't find nameless at the Plain of Death. Any tips?
There are four parts of the nightmare when you are your house. You need to go through all of them first. The 4th nightmare requires you to talk to the witch for mind protection. If you have completed all the tasks in the Iron Blood village and seen the 4th nightmare, there will be a new mission related to Groth scouting. It is in this mission that you will encounter the nameless.