The Bridge in Peril: How to Find Shades
You can pick the quest from a guard walking near the Northern Plains exit gate.
Guard informs you about the presence of large shade by the wooden bridge in the Northern Plains that is attacking people. He also says that the shade appears only when it’s cloudy weather. Guard needs your help in defeating the large shade by the wooden bridge in the Northern Plain.
The weather in Northern Plain does not change when you enter or leave Nier’s Village. So if you want to change the Weather in the Northern Plains, enter into other locations like the Forest of Myth and come back to the Northern Plains. You can keep exiting and re-entering the area to force the weather to change.