MTL - Portable Space: The Peasant Princess - Chapter 1301 twins

On the distant Tianxiu Planet, there exists a group of unusual and intelligent beings. They consist of neither children nor elders. They have neither birth nor real death. They are born into the world through an extremely special process and have managed to keep their fundamental memories of survival through their endless reincarnations.

They are the Tianxiu people.

For every Tianxiu person, if they find someone they like and want to bind as partners with each other — then they would have to go through a life or death Adult Ceremony. The winner of the ceremony will become the absolute dominant in this spousal relationship.

While the defeated one will be referred to as — Qizi.

- Description from Novelupdates

When Song Qinghan woke up, he found that he had not only transmigrated into another world, but also… had a ball in his stomach. He thought the original owner of this body had left a total mess to him. But it turned out there was a piece of precious jade hidden in it. Looking at the six-pack abs of Wu Dahu, he rubbed his hands with great excitement. Farming, your job! Hunting, your job! Giving birth, ahem, you worked hard! But surgery… leave it to me!

After being awakened from their slumber, billions of people found themselves dispersed in various sealed crypts. Surrounded by earth, they each had only a shovel.

Reborn as Red Army Misha!

- Description from novelbuddy