Immortality Begins With Internal Breathing - Chapter 11: Loyalty Comes First

He died on the wedding of the girl he had a crush on, after a long and successful career. After convincing Yama to send him back to the world, he decides to fix the areas in which his life went wrong. Realizing the lack of love and romance in his past life, he sets out to conquer the hearts of various women.

- Description from Novelupdates

Ryouma Takuma, a 39 year-old man with a hidden past, finds himself in a strange white room. There the gods tell him that he has died and that they are sending his soul to a different world; a world where magic exists. After living alone for three years his gamer soul loses common sense and starts toward crazy routes.

I am a female doctor, an obstetrician and gynecologist.

I have only two goals:

To make one person disappear,

To bring a child into this world.

Yet his fragrant medicine-scented presence

Blocks my way!

A man who was once called the world strongest agent ended up becoming a teacher after his retirement to train the new generation of agents. After many years of training his disciples, he is killed at the age of 60 by the ploy of a secret organization and was reincarnated in another world with all his past memories.Though he was surprised by the magic and the strange species of that world, he adapted very fast to his condition as a newborn and took advantage of it. He acquired special magic and gained a massive amount of strength thanks to his tight discipline in order to reach his goal: resume his career as a teacher which he left halfway through in his previous life.This is the story of a man who based on the memories and the experiences of his previous life, became a teacher who travels through the world with his new students.