Youkoso Jitsuryoku Shijou Shugi no Kyoushitsu e - Volume 4.5, Chapter 5: Classes Gathering Part 1

He crossed over to a new world where humans have magical power. They are called warriors. They use their power to kill the monsters that appear out of nowhere. Dragons, Dungeons, and Magic users are pretty common in this world. If you want to live in peace, you need to have that power. You can also become a powerful clearing dungeon.

In this dangerous world, he has a system that can help him grow stronger. But he didn't want to be a high-profile warrior who attracts much powerhouse attention or become a lab rat. He wants to be Low-profile and grow strong using his system.

The little handsome son-in-law passed through a world as waste material and the husband of a wealthy family. But because of his lacking aptitude, the wealthy family had driven him out. So he worked hard and found a more powerful family’s thighs to hold onto. Soon enough, he became the strongest son-in-law and husband in history.

In this world, it was impossible to practice martial arts. It was futile so he might as well take advantage of his wife’s thighs and maintain a comfortable and leisure lifestyle.

He’ll train his wife to become the strongest and best person in the world.

“Whoever dares to provoke me, let my wife kill you!”

- Description from Novelupdates

“How long has it been?”10,000,000 Years, a period of time which he dwelled in the endless abyss as a captive of war.After his fall, he lost everything to the hands of those who stand above the heavens.The twelve gods of the constellations, the Primal Zodiacs!Creatures who descended down from the absolute light to consume all.He fought against them only to fall prey to their destruction, locked away in the endless Abyss.Astroth Vermont lost it all, his will, his empire, his powers and his mind, all he knew was despair.But that’s until he woke up, Returning back to the world as someone else.The Blackest Evil was reincarnated as the Tenth Young Master of the Reinhart Family.His return is going to shape the world, returning all into chaos!Will he exact his revenge?Who knows, welcome to the land of carnage

A Speedster in a Fantasy World