"In the Upper Realm's Three Thousand Cosmos, there are powerful beings guarding each universe. If they were to slaughter wantonly, it would spark disputes. But the beings of the Lower Realm are frail; their blood and flesh are wondrous medicines for some Upper Realm powerhouses, whether for cultivation or for refining Divine Soldiers and Supreme Treasures.
Thus, the Upper Realm frequently makes a move against the living beings of the Lower Realm. To call it wanton slaughter is no exaggeration."
"However… although the powerhouses of the Upper Realm must regularly harvest the beings of the Lower Realm, they will not utterly exterminate the foundations of the Lower Realm. Even if a powerhouse emerges below, they do not wish to tear all pretense of civility with the Upper Realm.
They abandon a portion of the living beings and allow the Upper Realm to reap them. This is basically the tacitly accepted arrangement."
