Gekitotsu no Hexennacht - Volume 3, Final Chapter: That is a Small Light

Xiao Yu, who was a student from modern Earth, accidentally transports to another world and becomes the lord of a territory. Facing an unfavorable situation, he vows to take back his family business, build his new territory, kill all of those who covet his wealth, and dominate the world!

- Description from Novelupdates

Throughout this current life of mine, I will pay no attention to my past lives, nor will I seek future lives. I wish to live vigorously, to pay back debt of gratitude and fulfill duty to avenge, to defeat valiant heroes from all species, and to proudly laugh at all the Gods and Demons of the Six Path of Reincarnation!

[The Demon King is Dead], a story in which the Demon King got immediately killed in the Prologue. I became the ‘Demon Prince’ of said novel.

…Help me.

He was the CEO of the Mu’s Group. He had a respectable status and a domineering attitude. His biggest weakness was that he doted on his daughter. For his precious daughter, he came to her and signed a contract for her to be his daughter’s nanny. She thought it would be fine to stick to the contract, but he interfered more and more with her, driving away every man around her without leaving a trace, locking her in his arms, saying to her affectionately and tyrannically, “We should give a companion to our daughter.”