The Undead of the Dead

The powerful undead tribe suddenly secluded themselves from the world under the leadership of their clan leader. However, a prosperous race came to a point where it needed to rely on an outsider to save it. No one knows what happened, and seclusion may not change anything. After the undead prince with only half blood returned from the trial, what he saw was the devastated ruins of the undead. The prosperity of the past was like the dust that fell on the ruins. After landing, it was so inconspicuous...