Wortenia Senki (WN) - Volume 1 Chapter 14 - (Pursuers)

Karl Wagner is a disgruntled middle-aged instructor at the Bundeswehr Command and Staff College. He finds himself concerned about the direction which the German nation is headed in—just as he is killed by a terrorist attack. Only to awaken and find himself reborn as an infant, Bruno von Zehntner, the youngest son of a noble family renowned for its part in the German war industry a few years after the founding of the German Empire. Bruno, as he is now known, desires to rewrite history and ensure the German Empire emerges victorious in the coming century. And in doing so, finds himself entrenched in a world filled with Blood and Iron!

A mental patient, or a born policeman?

A peerless genius, or a master of crime?

There are cops who are least like cops, and there are criminals who are least like criminals.

Neither good nor evil is absolute.

It is a grey world we live in.

- Description from Novelupdates

Travel through Naruto and become the son of an ordinary civilian Chunin.

In this life-like world,

He obtained the golden finger to speed up the practice of ninjutsu,

Let ninjutsu itself produce a magical change from decay.

The knife cuts the jade, and the water bomb breaks Suzuo.

- Description from novelbuddy