I Was Possessed By An Unknown Manga - Chapter 13: The Secret of Strength

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

She was originally a puppet of her family. Pursued by the police for being a business spy and hitman, she was betrayed and fell into the sea.

When she opened her eyes again, she had turned into an ordinary high school student. Because of a disgraceful birth, she had been crowded out by her relatives. Because of inferiority complex and antisocial behavior, she was bullied by her classmates.

But now she is no longer someone who acts timid. Cheat her, and she will break your bones.

She possesses formidable Jade pupils capable of seeing through walls. Other people have difficulty breaking through jade, their sight for antiques is based on gambles, but she only needs a look.

An undertaking begins as she creates legends in the world of business.

Once upon a time, they laughed at her poor and destitute state. Now looking at her net worth of 10 billion, it can’t be explained.

To the relatives that come to hug her thighs, she must apologize: “We broke off relations long ago, so get lost!”

- Description from Novelupdates

With just three sentences, you convinced the Paladin to spend five thousand Gold Coins for you.You truly are a master of the Undead who thoroughly understands human nature!…“Respected Master Amberser, after our review by the editors at 'Legendary Spells' Publishing, we regret to inform you that your paper 'Research on the Non-Humanoid Form Modification of Undead Creatures' is unsuitable for publication in our monthly magazine. We suggest that you submit your work to a magical academic journal with less stringent review requirements.”A burst of ghostly blue flame erupted from the tips of fingers, reducing the rejection letter.“Damn it! You bastards are purely discriminating against liches, discriminating against undead magic!!!”“Drop dead!”

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.”