Global Reincarnation: Only I Know the Plot - Chapter 951:

“Born of Dragons, yet cursed by the Abyss—a king of two dooms.”----Ryuk Knull was nothing—just another powerless human in a world ruled by Titans, Vampires, and Fallen Angels. Until the Knulls came and took the only family he had left.On the brink of death, he awakened the Draconic Pets Evolution System—a power that doesn’t just tame beasts but binds them to his very soul. With it, mere monsters become apex predators.And Ryuk? He is their master.But power alone is not enough.He is a fusion of the most hated and the most divine—A being that should not exist.The abyss whispers. The dragons call. And when he rises—none will be spared.This is the Tale of the Abyssbourne Draconis!

After the death of her grandfather, Lu Xiaoxiao, a girl who lived in the 23rd century, lived alone in the villa left by her grandfather regardless of the dislike of relatives.

Suddenly, she found that her grandfather left her a space in Yu Peili. She likes to read novels, fearing that the end of the world will come, and she starts hoarding things desperately.

In the country, it became the body of an 8-year-old girl named Lu Xiaoxiao whose parents both died with the same name and surname. Fortunately, the space has come together, even in this strange era, I can live well

- Description from novelbuddy

Synopsis below:How did the Avatar universe change when a transmigrant appeared in an unknown village, long before the canonical events? And how are the two islands Kyoshi Island and Uzushiogakure no Sato (A village hidden in the maelstrom)?---Tags: AU, Before-canon, Post-canon, Violence, Death of major characters, Transmigration, Harem, Children, Incest, Romantic. Foul language.

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates