America Tycoon: The Wolf of Showbiz - Chapter 12 - Priority of Debts

Cassian Ven Dyke, the bastard son of a powerful ducal family, grew up in the slums of Veldora under the care of his father figure, sword master Russel. When Russel passed away, Cassian was left with only a silver necklace as his inheritance. After putting it on, Cassian was attacked by three psychotic thugs who tortured him in an attempt to steal the necklace. Refusing to give in, Cassian was ultimately stabbed through the heart with the very same necklace. Instead of dying, he mysteriously vanished as the necklace lodged itself in his heart. Just before disappearing, he heard an eerie message echo in his mind:[True mana detected. Origin: Human...][Human detected. Compatibility with system: Confirmed.]

Until he became the lowest-ranked master, his lonely and luckless life never changed.Suddenly one day, a descendant injected him with a nanomachine, and the machine started ‘speaking’ to him.[I am the seventh generation Nanomachine manufactured by Sky Cooperation, and I am operating as a central nerve connected to your brain.]“What? What are you talking about?”This was beyond the boy’s knowledge, he turned pale.The Nanomachine linked to his cerebrum realized the User was not understanding a single word it said.“Who are you, and why are you doing this to me?”[“I am the seventh generation Nanomachine.]“Nano Machine?”[Yes, Nanomachine.]The boy’s face hardened.Mashin was the deity the Mashin Religion worshipped, along with the Sacred Fire.The religions’ Master communicated with Mashin.“Um, are you really Mashin?”The boy knelt down and asked with a trembling voice. At this, the Nanomachine attached to his cerebrum realized it had been misunderstood.

Wang Xuan entered Longmao Square and was trapped in it. When he finally left, it turned out…

This is the last building on earth.

- Description from novelbuddy

A decade ago, the first dungeon gates appeared, but some vanished before they were ever conquered. The MC, a low-rank hunter, awakens the Lost Gate System, granting him access to these forgotten dungeons where legendary monsters and artifacts are trapped. Each completed lost gate grants him absurd power, but also reveals terrifying truths—these dungeons are prisons for ancient beings who want revenge.