MTL - Legend of the Mythological Genes - ~ A new book is opened, "If the World is a Game"

An unnamed 34-year-old Japanese NEET is evicted from his home following his parents' death.

Upon some self-introspection, he concludes that his life was ultimately pointless.

Walking down a street he intercepts a speeding truck heading towards a group of teenagers, in an attempt to do something meaningful for once in his life he manages to pull one of them out of harm's way before getting himself in the way of the truck and dying.

Awakening in a baby's body, he realizes he has been reincarnated in a world of sword and sorcery.

He resolves to become successful in his new life, discarding his past identity for his new life as Rudeus Greyrat.

Yao Mo Xin, the empress of Da Chu died in a cruel way a day after she gave birth at the hands of her husband the emperor, Ye Hong Yi, and her legitimate second sister, Yao Shu Ran. Ye Hong Yi got the throne because of the smartness of Yao Mo Xin, but he hated her because she made him feel like a useless person who needed a woman to become the emperor.

Her soul got in the body of her illegitimate third sister from the same mother Yao Mo Wan. Yao Mo Wan has the mentality of a child because the legitimate wife of her father fed poison to her mother while she was carrying Yao Mo Wan. Yao Mo Xin wants revenge for everything that happened to her, so she seduced the emperor and began her plan of taking everything away from him. She did that while pretending to still have the mentality of a child. She also wants to repay Ye Jun Qing back for everything he did for her while she was Yao Mo Xin. In the process of revenge, she met many people who will fall in love with her wit and intelligence.

- Description from Novelupdates

On the surface, he is the aloof and standoffish patriot whose sole purpose is to serve the nation. On the darker side, he is an invincible, powerful and mysterious man.