Itai no wa Iya nanode Bōgyo-Ryoku ni Kyokufuri Shitai to Omoimasu - Chapter 425

“I'm going out to do something, so I can't take care of you any more. You can go down the mountain and have fun. But if you can't find someone who matches your Innate Pure Yang Body in three years, you're finished!”These were the last words the old man, who was Lionel Yeager's teacher, threw to him before he vanished. Meanwhile, having mastered most of his master's skills, Lionel Yeager went down the mountain and took his first step into civilization for the first time in years.With his unparalleled medical and martial arts, he sets forth on a journey, befriending new allies and crushing all the enemies that stand in his way, as he attempts to resolve his Pure Innate Yang Body constitution, and cultivate to the top of the world!

A mecha otaku is reincarnated into another world as Ernesti Echevalier (Eru). In this world there exist huge humanoid weapons known as Silhouette Knight. Dreaming of piloting those robots, Eru, with childhood friends, Archid Walter and Adeltrud Walter: together they will aim to become a Knight Runner, pilot of Silhoutte Knight.

The reborn Prince Hechingen of the Swabian branch of the Hohenzollern family, sees the situation in Europe, and the war is about to start, so Europe doesn’t wait. Enclosure in East Africa, immigration development, and agricultural foundation, step by step, with the help of the crisis to achieve industrialization.

- Description from novelbuddy

Callius von Jervain.

A character who dies no matter what he does. A character who falls into a forced choice route where he can only die, no matter his choices up to that point. However, there is a single route where the character can live and play the game.

And I have to carve out that route somehow.

Because I’ve become Callius von Jervain in the game.