Qin Heng saw Dong Huaiyue's past.
Though the main purpose of exchanging lives was to gain the other person's insights into the laws, the course of one's life was an important part of forming those insights and could not be avoided.
He saw a human infant named Chen Jie being born in an antique house, received by a midwife, and then handed to a man named Chen Li.
That man was an emperor.
In other words, she had once been a princess of a feudal dynasty.
However, this emperor was not actually from feudal society. His memories told Qin Heng that Chen Li was an Earthling who had transmigrated to a place called Primitive Island. There, he led a group of primitive people in building infrastructure and making inventions, then fought his way out of that isolated island to contend against feudal dynasties. In the end, he defeated every nation of those feudal dynasties and became the ruler of the planet.
Of course, all of that had happened before Chen Jie was born. She only knew of it in broad terms and had not experienced it personally.
The life she had experienced was mainly the transition from the feudal era to the interstellar age—cultivating in childhood, rebelling in adolescence, then traveling everywhere with her father after reaching adulthood, venturing through the universe...
They took part in trials together, fought alien races together, and became True Gods together. In the end, under the hands of a Pseudo Origin Realm lifeform, they saved that universe. (For details, see the work Starting with a Group of Primitive People.)
After that disaster, Chen Li seized the universe's body, replacing the Universe Will and becoming the master of the universe. Using his own abilities, he captured a True God of the Mechanical Civilization and opened