(Um, Sorry) I’ve Been Reincarnated! - 013 – Mary San’s Diary

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 failed investor from 2017 got drunk and woke up in the 1980s. China is just opening up, and the economy is blooming. There is also the dissolution of the Soviet Union, the bursting of the Dot-com bubble and other financial crisis. He used his knowledge of the future and slowly build up his empire.

- Description from novelupdates

King Grey has unrivaled strength, wealth, and prestige in a world governed by martial ability. However, solitude lingers closely behind those with great power. Beneath the glamorous exterior of a powerful king lurks the shell of man, devoid of purpose and will. 

Reincarnated into a new world filled with magic and monsters, the king has a second chance to relive his life. Correcting the mistakes of his past will not be his only challenge, however. Underneath the peace and prosperity of the new world is an undercurrent threatening to destroy everything he has worked for, questioning his role and reason for being born again.