If becoming a "tool" is already an inescapable and cruel fate,

What's even more cruel than that is maintaining one's human nature throughout the process.

The real world is destined to have imperfections, but there will always be those who refuse to be assimilated into that imperfect part.

They must use reason, emotion, and all purposeful labor to fight against this fate.

...

In the year 4631 of the world calendar, a middle-aged man who had been imprisoned in a foreign land for many years returned to his homeland, and the story officially began from there.