Toaru Majutsu no Index: New Testament - Volume 18, Chapter 2: To Where Should You Flee? - Escape_to_Central.

This novel is also known as Gu Daoist Master

Humans are clever in tens of thousands of ways, Gu are the true refined essences of Heaven and Earth.

The Three Temples are unrighteous, the demon is reborn.

Former days are but an old dream, an identical name is made anew.

A story of a time traveler who keeps on being reborn.

A unique world that grows, cultivates, and uses Gu.

The Spring and Autumn Cicada, the Venomous Moonlight Gu, the Wine Insect, All-Encompassing Golden Light Insect, Slender Black Hair Gu, Gu of Hope…

And a great demon of the world that does exactly as his heart pleases!

—

*Gu (蛊) referred to poisonous insects in various cultures in South China while in folklore Gu spirits could transform into all kinds of species.

- Description from Novelupdates

After getting forcefully reincarnated into a world of an otome game he has no clue about, the protagonist is then killed and brought back to life by the prideful villainess with one desire.

To rule the world.

As the ruthless girl’s Eternal Servant, how will he dodge the fate that the game system has in store for him?

Li Yuanqing transmigrated and became the crown prince of Northern Kingdom. He was sent to the borders, after his cultivation and meridans was crippled, because he refused to marry a princess and was not allowed back into the palace ever.

Just then, the Hundred-fold Sign-in System was activated!

Outside his house in the Wilderness, he signed in and received 100 Replenishment pills!

Beside the lake of the Wilderness, he signed in and received 100 Marrow Cleansing pills!

Among the warriors of Myriad City Kingdom, he signed in and received 100 Heavenly Skill manuals!

…

Li Yuanqing had thought that if he just signed in silently and received the hundred-fold reward, he would be able to watch over his younger sister until she became the ruler of the kingdom and until he became invincible.

But he had never thought that one day, the queen of Myriad City Kingdom would come to meet him!

“I am willing to use Myriad City as my dowry. Will you marry me, Your Highness?”

Li Yuanqing did not know what to do when he looked at the queen smiling beautifully before him…

One scam package,That's all it took to drag the 17-year-old Cail into the world of the void....He thought he had ordered a limited-edition sneakers. But what came was a shady-looking package on his front gate. It smelled like rotten egg and sulfur. Inside the package was a strange box.It's filled with eccentric junk. They looked very intricate and mysterious. He thought, “I probably got someone else's package, a package from someone that was very interested in mysticism.”An old coin, a cracked compass, a ring with an ugly center stone, and some other weird looking trinkets.So he did what any broke student would do:He sold it. He figured someone might want them for cosplay or something. Well, except the gold-rimmed glasses that seemed to fit him very well.“Damn, I paid 7,000 nu for that sneaker; I better get something out from this scam package.”Then all hell broke loose. Strange people started approaching him.People brought that junk. Very strange people wearing suspicious get up trying to buy those stuff in the sketchiest manner possible.As he kept selling, he realized that the box was refilling, it seemed to have an endless supply of those strange stuff. Those people called it 'artifacts'.Then one day he woke up with a strange tattoo on his arm; inside the tattoo was an independent space containing the box. It is basically inseparable from him.“I didn't ask for any of this to happen. But now, strange people come to me with desperate offers. Money, memories, and even soul.”He's just trying to survive high school while earning some money!He had no idea what was going on, but apparently, this thing that he got? It's not just an artifact. It's a contract.As Cail navagates school life, part-time jobs, and otherworldly clients, he starts asking the real question:When did I become an artifact dealer?!By day, he is just an ordinary student, a NPC character.And by night? He is The Dealer. Selling ancient items and dealing with people that he probably shouldn't be talking to.“Since I'm already in this mess, might as well profit off of it.”