According to the deduction by the Goddess of Magic, Milmina, the current state of the entire wasteland is equivalent to an out-of-control and internally closed "abnormal energy field." The massive explosion of the Well of Deep Blue and the aftermath of the past "Pre-tremble of the chaotic wave" are bound to this land, forming a large-scale and unquenchable magic shock. According to the "Unified Wave Theory," the boundary between "reality" and "illusion" in this world is ambiguous and changeable. Therefore, an out-of-control energy field means the material world will also lose control. Some things will spontaneously generate at energy focal points, things that should have vanished will be reorganized and reappear, and those without protection will suffer irreversible harm in such an energy field.
This is the truth of the wasteland—and the Barrier Wall's "healing" of the wasteland is essentially to "smooth" and "filter" this large-scale abnormal energy field.
