The Ruler Of Darkness - Chapter 18Book 4:

In a certain empire, a young prince was born with a golden pickaxe. It should have been seen as a miracle or a blessing, but instead, the emperor wanted nothing to do with the child. He refused to accept a prince blessed with what he considered a commoner’s job, fearing it would taint his royal bloodline.Abandoned by his own parents, the young boy, Shennong, was taken in by a succubus.But neither the succubus nor the emperor knew the truth about him—Shennong was no ordinary child. He was a reincarnator.This is the story of how the world of Matay reacts to the birth of the first Sandboxer, a class unknown to many. Will Shennong forgive those who abandoned him? What was the purpose of his reincarnation in this world? What is the true nature of the golden pickaxe, and what does it mean for Shennong?One thing is certain—Shennong is not alone in this world because he had a true sandbox system and people to support him even in this world.Join him and experience a true sandbox adventure!

Luis Hartmann activated the mysterious Portal and began the journey of traveling between two worlds. In Immortal world, there are various immortal cultivators who can destroy mountains and live for thousands of years. In his own world, it is a Western fantasy realm where people can become knights or wizards, with different kinds of races. Luis, using the resources of both worlds, rises through the ranks. The life seed that knights awaken when becoming apprentice knights transforms into spiritual roots in the immortal world. With strategic wisdom, he helped his family become the eternal family, dominating both worlds. [Knight + Martial Arts + Immortal Cultivators + Family building]

This is the story of a young man who was reincarnated as a dragon with a near-insatiable curiosity. Initially sparked by questioning his own reincarnation, he quickly gets lost in the endless world of magic, using his deep understanding of advanced sciences to learn the laws and properties of a new type of energy known as mana.However, soon enough, the table would flip, and he would begin using that very same energy to expand his knowledge of science, to the point that he would begin questioning his own understanding of the world.Although not his original intention, with the combination of his intelligence, expanding curiosity, and the 'miracles' that occurred to allow for his existence, he quickly found himself climbing the mountain of strength as if it were a small hill before eventually climbing to a point where it seemed as if he himself was the peak itself.Even if.. that was never the case...There is mild gore, and profanity is 'censored' toward the beginning, but not later in the story.

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.