All The Skills - A Deckbuilding LitRPG - Book 5:

An unexpected event led her to become pregnant, and after the child was born, he actually sent someone to take her son away.At the top of the cliff, the car was destroyed, and lives were lost.Years later, she returned from abroad, looked at the man before her, and said coldly, “Mr. Mu, even if you offer your entire company, I won't do business with you.”

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.

Yuki, a high school junior, dies heroically saving a stranger and is reincarnated in a fantasy world, where he discovers an extraordinary and unrivaled power.

After the Catastrophe, every rule in the world was rewritten.