World state: In the 78th year of the "Shattered Sky Era", the sky is filled with "voids" that swallow up light. The land is divided into "barrier cities" (remnants of human strongholds), "rust belts" (ruins of old cities), and "eroded soil areas" (lairs of strange spirits with disordered rules); foreign spirits are divided into "reverberations" (energy fragments without autonomous consciousness), "resentful skeletons" (entities containing negative human emotions), and "lawful spirits" (rare neutral spirits that guard specific ruins).
