The inhabitants from the old civilization are not all extinct, even two centuries after the fall. A few people managed to escape the catastrophe caused by the AIs, relying on immortality technology to continue living in the New World. They still retain the memories of that glorious era, and hold onto its lost knowledge and secrets. People in the New World call them Seireis (living ghosts). Some live in seclusion beyond the boundaries of the New World, while others hide their true identities and try to blend in with the people of the New World.
Seireis are well aware of the risks brought by exposure of their identity. The vast majority of people in the New World believe that immortality is a curse that resulted in the destruction of the old world: gaining eternal youth greatly increased the fear of accidents that might lead to death. People were no longer interested in anything that involved risk, so mankind abandoned their dream of colonizing the stars. They decided all their desires could be safely satisfied in a virtual world. Autonomous thinking machines took all the responsibilities of running and supporting mankind’s society, acting as their nannies and servants. When the AIs decided to replace their masters, it was too late for mankind to resist them.
The new civilization that rose from the ruins hates the corrupted lifestyle from the old world, which leads to their hostility towards the Seireis. They worry that the temptation of immortality may lead them into another extinction. However, many great powers in the New World still desperately want to find these inhabitants from the past, driven by different reasons and ambitions. Some hope to obtain advanced technologies, some want to find a way to live forever, some want to use the Seireis to discover the treasures buried in the ruins of the long-dead civilization.
Yuki was born at the pinnacle of the old world. She experienced that era of pride and corruption. In the last days of this once glorious civilization, mankind executed operation “Exodus” in desperation, a plan to transform as many people as they could into full-body cyborgs. These advanced biochemical bodies can withstand harsh environments and sustain life for a long time in a semi-dormant state. By hiding in shelters buried deep underground, they were designed to be the seeds to rebuild mankind in the far future, when the threat of the AIs had passed. Yuki received the most advanced cyborg body from the Exodus project. This perfect body has built-in fusion reactors that can maintain operation for thousands of years. The nano-cells within the cyborg body will also continuously repair any damage to the human brain, which allows the host’s memory and personality to be perfectly preserved.
Yuki used to be a historian. In the last days of the old civilization, she realized the true source of the destruction of the world she lived in was not the rebelling AIs, but the corruption of mankind itself. She hoped to use her knowledge to help rebuild society in the distant future and prevent people from repeating the same mistakes. When she woke up again, she found civilization had been revived already, and survivors like her are not welcome in this new age. Having lost her mission, Yuki lives alone in the ruins. She misses the family and friendships she once had. She strives to remain optimistic; driven by her loneliness, she wants to find a new purpose for her own existence.