天人の幽鬼

They are the wicked legacy of the Celestials, a "calamity" forever etched into human history.
Their grotesque and malevolent forms are said to resemble the Celestials themselves.
There are several variations of them, and they attack the cities where the remaining humans have survived, often in swarms.
Even the academy cities, protected by the "Jewel Princesses" and Guardians, are not exempt from their assaults.