Earth's Immortal Past

When cultivating immortals became the focus of civilization, elites fled into deep space with their resources, and the last monks left behind on the earth split in the countdown - the reappearance faction spent all their resources and bet on a savior; the resonance faction deciphered the whispers of the stars and sought reconciliation with the universe; the guardian faction maintained silently, guarding the last step of humanity. Is the chaotic "star echo" a warning from the universe, the last words of the undead, or the heartbeat of the Cleaner before he wakes up?