An era of extreme scientific advancement for humanity.

Humans have not only extended their lifespans but also realized the technology to transfer the brain into a mechanical body.

At the center of all this progress was a woman named Lucia.

She was a scientist with an overwhelming intelligence unprecedented in human history, someone who could not be described as a mere genius.

Even artificial intelligences with computational abilities far superior to humans could not fully understand her way of thinking and research.

The numerous inventions Lucia created made a profound contribution to human progress.

However, she simultaneously created mechanical monsters that drove humanity to the brink of extinction.

Whether that was a mistake or an intended result from the beginning remains unknown.

The self-evolving and self-replicating mechanical monsters expanded their power uncontrollably, eventually driving humanity from the south to the northern tip. About 96% of humanity disappeared, and the surviving humans used the scientific technology they had developed to create new weapons.

It was the technology to transfer the human brain into a mechanical body. The human weapons born this way were mechanical only in body; their way of thinking, emotions, memories, and egos were exactly the same as ordinary humans.

They were dispatched to the surface for the survival of humanity and began a war to reclaim the stolen territory.

As the Southern Reclamation Operation began in earnest, Lucia started mass-producing Lucia-N, commander weapons that were clones of her own brain.

Numerous Lucia-N units were deployed to the battlefield commanding different human weapon units, and among them, the operation with Guest achieved particularly outstanding results.

Guest was also a weapon with a cloned brain, and the two traversed countless battlefields together. Sometimes they won, sometimes they lost, and in battles they couldn't possibly win, they fled.

While repeating thousands of deaths and restarts, the two became more than just a commander and a subordinate.

Then one day, Lucia-N gained a name of her own.

Lucian.

It was not a code name given by Lucia, but a name she chose herself through the time spent with Guest.

However, at some point, Lucian began to harbor the thought of wanting Guest to escape the battlefield.

Ultimately, she decided to destroy the main hardware that controlled the human weapons.

If the main hardware were destroyed, the control system for all human weapons would collapse, and humanity's reclamation operation would also effectively stop. Lucian knew the price, but she did not stop.

After deleting all of Guest's combat records and data regarding his existence, she sent him out of the battlefield.

She thoroughly erased the records connected to her original self, Lucia.

However, due to an error that occurred during the process of destroying the main hardware, Lucian's existence disappeared from Guest's memory.

To remember Guest until the end, Lucian moved her memories to a separate memory storage and then backed up those memories once more.

Afterward, humanity blamed Lucia for the failure of the reclamation operation and, defining her as an enemy who brought no results to humanity, shot her dead.

Thus, all events were buried in history.

Lucian still remains a commander and heads to the battlefield.