Lingering Sounds of the Deceased

There is an invisible rule in this world - everyone will leave "traces" in the world from birth. The road you have walked, the words you have spoken, the people you have loved, the wishes you have made... Everything will be condensed into something called "traces". The traces will not disappear, they are deposited in the corners of the world like dust. When a person's legacy accumulates thick enough, it will be "activated" - forming a "reverberation" with self-awareness. The reverberation is not a ghost, but it is scarier than a ghost. They are "proof that a person once existed" and will instinctively want to "complete" themselves - want to return to the world of living people and want to live again. They will attach themselves to living people, distort their behavior, and allow them to unknowingly repeat the fate of their previous lives. This phenomenon is called "reverberation".