A Thought Through Eternity - Chapter 13 - You can come too!

Ye Xiwen was previously only an ordinary university student on Earth, but unexpectedly crossed through into the world known as the Zhen Wu Jie world! In this world, formidable warriors are capable of turning over mountains and collapsing the ocean, destroying the sky and extinguishing the earth! He originally had ordinary aptitude, because of that he received the mysterious special space! Any martial art can be deduced within the mysterious space, other people practice for decades, he only needs a year! So long as he has enough spirit stones, any talents he faces are all floating clouds!

- Description from Novelupdates

One day, Yoichi who grew up while not knowing his parents has received the news of his father’s death. His father left behind a testament——which said he is to pick only one out of five ‘little sister candidates’?!

Mu Yangling was reborn in the family of Orion. He thought he could live a simple and happy life. Who would have thought that a military disaster had nearly destroyed their family. His father was classified as a military household, and their family accompanied them to farm the fields.

Unfortunately, they could not even tell the seedlings of grains. Qing, looking at his mother and younger brother who were about to cry without tears, Mu Yangling raised his chest and said, “It’s okay, I have the strength” and some agricultural theoretical knowledge from a thousand years later.

- Description from novelbuddy

In the world of Norse mythology, a human boy falls in love with Waltraute, the fourth Valkyrie sister. He wishes to marry her, but Waltraute gives him an impossible challenge to deter him.

Nevertheless, the boy is determined to carry out the dangerous task and to marry Waltraute afterwards.