In DC/Young Justice with the Omnitrix/Ultimatrix and a Chat Group - Chapter 13: I see... I know where I am now.

Zhong Li, an orphan in the 21st century, was wondering how to collect the fees for his college study on the street, when he was suddenly hit by a car, which threw him into a river. An orphan’s disappearance would not bring too much attention to the world, but this accident gave Zhong Li another chance of living a glorious life in an immortal world. When he woke up, he found himself lying in a magnificent yet strange palace built of all gold, but had no door. An immortal claimed to be his savior and wanted to train Zhong Li with all of his cultivation methods, only because he was too lonely and wanted a disciple to keep him company. When Zhong Li finished his study, the master would tell him how to go out of the palace. Zhong Li never thought that the path to immortality would bring him to the fate of becoming a dragon.

- Description from Novelupdates

I became the Heavenly Demon’s dog.

The tale of Oliver.
An orphan boy from a Mine, in 19th century Europe, filled with Magic.

Choi Sunwoo’s life takes a dramatic turn when he wakes up as a character in the very novel that enthralled him for weeks. Working as a publishing company PD for five years, Sunwoo is no stranger to dramatic twists, but nothing prepares him for this surreal twist of fate. Now pregnant and trapped in a cursed narrative, he becomes an integral part of the story he once read. Sunwoo’s character, an ambitious Omega, daringly infiltrates the secretariat under the guise of a Beta, all to be near the enigmatic and dominant Alpha, Kang Jinwook. His bold plan spirals out of control, leading to a scandalous pregnancy and a botched blackmail scheme. As he attempts to extricate himself from this tangled web by resigning, he finds himself the focus of Jinwook’s intense and obsessive desires. Will he outwit Jinwook and break free from the novel’s grip, or will he be forever ensnared in its pages?