Moto Sekai Ichi'i no Sub-chara Ikusei Nikki - Chapter 31: Everything Was Overturned

Seven years ago, she freely and easily abandoned ￥100 and ran away, carrying her unborn son with her. Seven years later, she returned with the lady killer’s genius son, never expecting that her darling son would sell her out to MBS International. Unexpectedly, her immediate superior was the Mr. ￥100 from seven years ago!

Once upon a time in a modern city, a man died and was reincarnated into a body and a new mythical world.

This world holding many secrets, and wonderous things, but he possessed something that was highly regarded in terms of importance and usability: SPEED.

Join Noah on his quest to acquire great power, meet new people; while also discovering the many mysterious features of this new world he'll eventually learn to call his home.

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

This was a world ruled by summoners. In this world, summoners were the most remarkable existences that took center stage. When the mysterious, higher world was within reach, when the recollection of the glorious Huaxia civilization overlapped with reality, the story of the summoners in Great Flame Republic unfolds…