Elf Tensei Kara no Cheat Kenkoku-ki - Chapter 9Book 4: -3: The Arrival of the Young Lady

Roy’s life was nothing special. The only thing commendable was the last few moments when he saved a mother and her child from a drunk driver.
…
It’s really an egg! Damn it, what kind of monster have I become? Did I fall into Hell instead of making it to Heaven??
Join Roy as he ventures through various worlds with the Custom Made Demon King System—a system that allows Roy to draw anything he can imagine and create it through exchanging souls!

A war veteran and an anime fan as well, he got into anime by watching it with his grandson after his retirement, his grandson loved pokemon and so did he also came to like this world of pokemon where people didn't kill each other and people used to have fun with there pokemon, after watching Pokemon with his grandson and playing with him all day he got back his childhood which he could never experience due to the cruel war, and as of now our MC has turned 82 years old he was very satisfied with his life with no regrets and waiting for death to take him away but will death be is end or will it start a new beginning, a new legend.

Her – a glutton without troubles or worries who crossed over and became a young fat chick with a deep vengefulness.

Him – a young master of the number one power; a two-faced man with elegance and charming, good looks; he is the chosen one of the former saint god and a man who will only bend his back for her alone.

This domineering crossover’s slogan is, ‘Don’t touch if it is this sister’s, put it there if it isn’t this sister’s!’

…watch how the Domineering Glutton and the Two-Faced Venerate Emperor create sparks as they meet and collide, stirring the whole Spirit Treasure Continent into turmoil, how they fall for each other and how they kill each other, how life and death severs love.

- Description from Novelupdates

Reborn as a poor young man in an unknown mountain village in another world, Lu Qing expressed his helplessness.

Fortunately, he awakened a power that could see through item information, which gave him some capital to survive.

He looked at a weed on the side of the road.

[Ox bone grass is of average quality and can be used medicinally. It is quite effective in treating bone injuries. 】

Look at the red carp in the river.

[Red Moon Carp is of high quality, with delicious meat, and is a top-quality nutritious food. 】

Look at a hare in the mountains.

[Gray rabbit, common hare, edible. 】

…

Relying on his own supernatural powers, Lu Qing gradually established a foothold in the village and was able to survive.

Just when he thought that he would spend his life peacefully in this ancient world with low productivity.

One day, he suddenly saw a figure flying past in the sky…

- Description from novelbuddy