Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 17 - 17-7. Reason Behind the Taboo

Liu Yan, an ordinary office worker from Earth, unexpectedly traveled to a strange world.

The heroes of the ages are on the side, embarking on a journey to conquer the heavens.

- Description from novelbuddy

The world spat on him because he betrayed humanity and took the side of darkness.His executioner was his best friend and his lover stood on one side, her eyes hollow and devoid of any sympathy.Every single one desired him to vanish.However, the moment his pitiful life came to an end he found himself getting summoned by a Goddess.Kneeling on the ground and requesting for his help,[For the last time, please wear the mantle of our champion again. This world needs you, Clarsen.]So she said.The world would be pushed under the darkness of death again, and this time there would be several chosen warriors there to save the world.Yet, despite all that, the eldest Goddess was begging for his support.“Fine, I will do it myself.”********Additional tags: Strong to stronger, ruthless MC, kingdom building, limitless mana, possessive characters, regressor, transmigrator, obsessive love.*********A/N:- Give the story a read until it goes through a time skip. I request you to pass the judgment after that.

Starting as a fallen noble? Struggling with hunger? Having to pay high taxes to the king? If you don’t pay enough, your head will be chopped off?Romon activates the Lord Simulator and begins with a village...[Your subjects discover a large amount of magic crystal ore while digging on the western side of your territory!][Your territory's culture improves, and your rapid-fire mage develops: Orbital Magic!][You successfully expand your territory and discover an underground labyrinth city on the new land!][You annex the land and gain a new title: Duke of Thune!][The king passes away, war breaks out, and you decide: to annex all lords and establish a new kingdom!]Romon: “Annexing the world is for better simulation, leading the world to ascend efficiently—how can you call it personal ambition?”

The world that nurtured the civilization which reached the pinnacle of magic was on the verge of destruction.
The last survivor transmigrated to the past, when the magic civilization started growing, as countless mages were still fumbling their ways through the thorny paths of magic knowledge.
He, who came from the end of the magic era, aim to reach the pinnacle of magic.

- Description from Novelupdates